- [Narrator] With more than half the global population now living in urban areas, mega cities are on the rise.

(dramatic music) Home to 10 million people or more, their skylines are defined by soaring apartment towers and sprawling shantytowns.

Within ever expanding city limits, rapid urbanization has spawned a tsunami of challenges; Congestion, air pollution, unemployment, and crime.

But beneath their often gritty surfaces, mega cities set the tone for some of the most vibrant cultures on Earth.

Small wonder they've earned their place among the world's greatest cities.

(dramatic music) Exactly where mega cities begin and end is hard to define as each great city draws a different line.

But the city with the greatest number of people living within it's official city limits is Shanghai.

A churning, industrial colossus, a titan of manufacturing and trade this megatropolis is home to more than 24 million people.

And as that number increases by 46,000 each and every day, Shanghai maintains a firm grip on the title of world's most populous city.

Situated at the meeting point of the great Yangtze River and the South China sea, Shanghai is the epicenter of China's economy.

Founded during the Song Dynasty around 1,000 AD, Shanghai's development was relatively modest until a significant turning point in the mid 19th century.

Following the British victory in the opium wars, China was forced to open up Shanghai's ports to foreign trade.

As a result, Shanghai flourished, as it became a global center of commerce.

Foreign influence from this period is still evident today.

Renowned for it's intercontinental ambience, The Bund, an esplanade along the banks of the Huangpu River, maintains foreign street names and various styles of 20th century western architecture, as testament to the city's brief but influential colonial history.

Ultimately, China had its own plans for Shanghai.

In 1949, the ascendant Communist party imposed heavy trade restrictions upon the city.

But as foreign influence declined in Shanghai, so did prosperity.

Fortunately, this downturn was relatively short lived.

In the early 1990s, economic reforms in the middle kingdom paved the way for the port city's resurgence onto the world stage.

With the nation pivoting away from Communism to a Socialist market economy, President Deng Xiaoping's vision was to develop Shanghai into a global city that rivaled Hong Kong.

Today, Shanghai boasts the world's largest port, the gateway to the city's epic manufacturing industries, a financial powerhouse that makes up a whopping 20% of China's GDP.

As China's wealthiest gateway city, Shanghai has become the nation's most cosmopolitan.

While Chinese culture and traditions are evident in all facets of street life, the city exudes modernity.

As young fashionistas pound the pavement in search of the newest fad, older inhabitants practice the ancient art form of tai chi.

Originally conceived as a martial art, it is utilized as a means to achieving good health and longevity in an increasingly fast paced world.

(gentle music) Perhaps nothing illustrates the duality of this emerging city better than the skyline of Pudong.

Viewed from the historical Bund Promenade, the vista is more akin to the setting of a sci-fi film than an ancient Chinese city.

Incredibly, this area was little more than rice paddies as recently as 25 years ago.

Today, Pudong's skyline is synonymous with wealth and power.

Home to numerous global companies, the area is considered a special economic free trade zone.

A piece of capitalism in the heart of Socialist China.

Amongst it's more notable buildings is the rocket-shaped Oriental Pearl TV and Radio Tower, the Shanghai World Financial Center, affectionately known as the Bottle Opener, and at 128 stories high, China's tallest building, the Shanghai Tower.

(dramatic music) Shanghai, the world's most populous urban center, is an ancient city with its sights set firmly on the future.

Rapidly reemerging onto the world stage, this is a mega city on the rise.

(dramatic music) Exotic, enticing, and intoxicating.

Bangkok is a deliciously spicy city that tantalizes locals and foreigners alike.

The capital of Thailand, Bangkok is surprisingly the only metropolis in the famed kingdom, a nation otherwise dominated by agriculture.

With a population nearing nine million Bangkok is technically a mega city in waiting.

But when taking its vast urban sprawl into account, the head count soars towards a whopping 15 million residents, making this region one of the most populous in Southeast Asia.

Nestled along the banks of the Chao Phraya River, Bangkok has been the capital of the kingdom of Thailand since 1782.

The city was founded by the Chakri Dynasty, a monarchy that reigns to this day.

The grand palace located in the heart of Bangkok was once the official royal residence.

But its purpose is now largely ceremonial.

The grounds, and several temples within the complex, are open each day to the public.

The temple of the Emerald Buddha is regarded as the most sacred in Thailand.

The revered statue for which it is named was carefully carved from a single block of jade.

With up to 95% of the population adhering to the faith, Buddhism is Thailand's official religion.

There are over 40,000 temples or wats as they're locally known, throughout the country.

Many of the largest and grandest are located within Bangkok, visited by millions of devoted locals and curious tourists every year.

On the banks of the Chao Phraya is Wat Arun, arguably the most spectacular of the city's temples.

The grounds are magnificent, as are the statues housed within.

(light music) Before the advent of state funded schools, these temples also acted as valuable centers of learning.

Known as Children of the Wat, there is a long history of youths joining monasteries in order to gain an education.

The tradition continues today, though in significantly reduced numbers.

Praised for their discipline and devotion, the local community holds these young monks in waiting in high esteem.

There is of course another temple that is widely worshiped in Bangkok: The Temple of the Body.

By catering to this largely western cult, Bangkok has carved out an international reputation.

(rock music) The backpacking center of the universe.

Khao San Road is awash with bars, tattoo parlors, and tour operators that promise the adventure of a lifetime.

A mecca for scantily-clad, body-conscious 20-somethings.

The highly westernized district is a respite from all things Asia, a weary traveler's paradise.

A short rickshaw ride away is Patpong Road.

Catering to more carnal desires, it's Bangkok's red light district.

Repelling, and yet somehow compelling, this seedy underbelly is jam-packed with adult-themed entertainment, from go-go bars to fetish clubs.

The sex tourism industry, worth a staggering 3.5 billion US dollars a year, has earned Bangkok the rather dubious honor of being the sex capital of the world.

While some find solace in pleasures of the flesh, others unwind by partaking in a few hours of retail therapy.

And in this endeavor, Bangkok doesn't disappoint.

The Chatuchak Weekend Market, with a whopping 8,000 stores, is the largest of its kind in the world.

But Bangkok's most endearing shopping experience is to be found outdoors.

Stemming from the Chao Phraya River is an intricate network of canals.

Making use of these abundant waterways, charming floating markets are scattered throughout the city and its surrounds.

They sell everything from fresh produce to piping-hot river food.

This rich river culture has earned Bangkok the nickname Venice of Asia.

(woman vocalizing) Originating in the hinterlands of the north, the Chao Phraya River carries produce from agricultural regions to the capital, where it is chopped, boiled and fried into some of the tastiest dishes in the world.

They are as rich and as exquisite as the nation's history and culture, and inextricably linked to both.

Rice in Thailand is sacred, and every grain is said to have a divine element within it, so nothing is ever wasted.

Eating alone is a gesture of bad luck, so meals are always shared.

Dishes invariably blend five tastes; Salty, sweet, sour, bitter, and spicy.

A metaphor for Bangkok itself.

As food is a huge part of Thai culture, it should come as no surprise that the city is home to the world's largest restaurant.

This enormous food hall boasts a floor area five and a half times the size of the White House.

(dramatic music) If New York is the city that never sleeps, then Bangkok is the city that never seems to stop having fun.

Traditionally, the locals usher in the new year by first giving alms to the monks before launching into merrymaking with a vengeance.

The showpiece of new year celebrations, known as Songkran, is one enormous, boisterous water and chalk fight, where the young and young at heart partake with reckless abandon.

(upbeat music) The festival's as enigmatic as the city itself, honoring the past and the present, the old and new.

By not taking itself too seriously, it accepts the good and the bad.

And it celebrates with a great deal of fun the very notion of unity.

The coming together of the sweet, sour, salty, spicy, and bitter elements of life in this most vibrant of mega cities.

(dramatic music) As cities go, there are few in the world as overwhelming as this one.

Delhi simply assaults the senses.

With a history that can be traced back to 3,000 BC, it's a city that does not shy away from its past, nor make excuses for its present.

Rich and poor, sacred and secular, its split personality even ventures to divide Delhi physically into the old and the new.

Forged in the shadow of the mighty Himalayas, with a population of over 16 million, Delhi is the capital of India.

The world's largest democracy, and second-most populous nation on earth.

When India gained independence from Britain in 1947, the young city of New Delhi, a district within the territory of Old Delhi was named the capital.

But that wasn't the only change.

British India was to be partitioned, creating two new sovereign nations, divided by geography and religion.

This partition set in motion a mass migration event, one of the largest in human history, as swarms of Hindus left Pakistan for India, and Muslims, vice-versa.

In all, nearly 12 million people were displaced.

With the influx of Hindu refugees from Pakistan, the city's population doubled within a decade.

(gentle music) Today, Delhi is replete with monuments that reflect note by note the rich history of India.

Built during the 1500s, Humayun's Tomb is said to have inspired the Taj Mahal.

Commissioned by Moghul emperor Humayun's Persian wife, the exquisitely balanced building cleverly mixes Persian, Islamic, and Moghul styles.

Even Humanyun's most trusted razor-wielding barber got a prized resting place in the magnificent burial chamber.

The Red Fort, commissioned by the Moghul emperor Shah Jahan in the 1600s was designed by the same architect responsible for the iconic Taj Mahal.

A more recent addition, the India Gate pays tribute to the 90,000 Indian soldiers who lost their lives fighting for the British Army in the first World War.

An eternal flame was added in 1971 to honor those who fell during the Indo-Pakistan War of that year.

Although sectarian, the city is not without monuments to its Islamic past.

Jama Masjid, completed in 1656, is one of the largest mosques in India.

Capable of holding 25,000 in the courtyard alone, it was once occupied by the British military, which used it as a garrison.

(light sitar music) Despite its tumultuous past, Delhi continues to thrive.

Its huge population services a wealth of industry and commerce, and as a hotbed of politics, decisions made here reverberate around the nation.

The many residents navigate their way through the mayhem in buses and auto-rickshaws.

By law, these tiny taxis and overburdened buses run on natural gas to keep air pollution to a minimum.

A sea of yellow and green funnels commuters through the city's crowded streets, to and from work, shops and markets, many of which are tiny, family-run businesses.

Culturally and spiritually significant to Hindus, flowers are abundant throughout the city.

Used as garlands and offerings, their bright colors and pungent fragrances assault the senses, as do the spices.

Famed the world over for their rich and diverse flavors, these spices are central to the political history of the city, given their value is precisely what made Delhi so attractive to the British.

Responsible for the rise and fall of empires, India's spice and silk trades still thrive today.

Another decidedly Indian institution alive and well in Delhi is the dhobi gats, or open air laundries.

Here, 5,000 dhobi wallas and their families manually wash and air the city's dirty laundry.

Despite the availability of modern machines, the tradition lives on.

Having endured occupation, segregation and mass migration, the Indian capital maintains a unique collective identity.

But only by learning to celebrate unity in diversity will Delhi's 16 million residents truly overcome the adversities of the past, and move towards a brighter future.

(dramatic music) (dramatic music) Built on the vestiges of an ancient civilization, it could be said that modern-day Mexico City stands on the shoulders of giants.

Despite being situated in Central Mexico's Valley of the Damned, it has grown into the largest metropolitan city in the Western Hemisphere.

(uptempo Spanish guitar music) Home to over 10 million people, it is the oldest capital in the Americas.

Occupied by ancient peoples for more than 10,000 years, the Valley of the Damned was chosen as the site for the Aztec capital Tenochtitlan in the early 14th century.

(mysterious music) A prophecy foretold of a land of plenty, marked by an eagle with a snake in its beak, perched on top of a cactus.

And legend has it that that is exactly what the Aztecs found when they ventured into this valley.

Enduring in Mexican folklore, this image is the centerpiece of the nation's flag.

Within 200 years, Tenochtitlan had grown into the largest city on Earth.

But the meteoric rise of this early mega city was to be short lived.

Drawn by the promise of gold, the Spanish razed the Aztec capital to the ground during the conquests of the early 16th century.

Today, little remains of the original Aztec city.

Realizing the symbolic significance of the ancient capital, Spain built its colonial capital, Mexico City, on the original site, essentially removing all trace of a once-powerful nation.

But, they say that time heals all wounds.

And today, the Spanish architecture that endures around the city is no longer regarded as a symbol of oppression.

In fact, many of these buildings pay homage to a proud and ancient lineage.

(upbeat music) At the Palace Nationale, the murals of Diego Rivera tell the tales of pre-Spanish indigenous life, through to the revolution and beyond.

While at the Museo Nationale De Antropolgia, curators have given native and Hispanic peoples their own space, presenting pictures of life from the past and present.

Born from this collision of cultures is an art form with a distinctively Mexican tone.

The roots of mariachi music can be traced back to the early 18th century.

Combining uniquely Mexican melodies and rhythms with singing, dancing and performance, the elaborately adorned artists imbue the heart and soul of the Mexican spirit.

If there is one thing that Mexicans love more than their music, it is surely their food.

From tacos to nachos, chimichangas to burritos, Mexican cuisine is famous the world over.

Dotted all over the city, colorful and vibrant markets serve a wealth of culinary delights to the hungry masses.

(upbeat mariachi music) The wonderfully multicultural identity of this eclectic mega city has been forged in the fires of adversity.

It's perhaps the historical trials and tribulations that have shaped this ancient capital into the thriving urban center we see today.

Fulfilling an ancient prophecy, Mexico City has indeed flourished into a land of plenty, if not the one imagined by its original inhabitants.

(dramatic music) Throughout its history, Moscow has been a city in flux.

It has risen to great heights, but also fallen from grace.

Today, Russia's capital is a far cry from its recent past.

Not long ago a staunchly Communist enclave, Moscow entered the 21st century as a fast-paced, modern metropolis and thriving hub of capitalism.

With over 13 million people living within its city limits, Moscow is Europe's largest urban center.

No surprise then that it's also the political, cultural, scientific and economic capital of Russia.

Ruled by tsars and powerful empires, sacked by Mongols and Nazis, Moscow lays claim to a turbulent history.

(men vocalizing) Reinstated as the capital following the Russian Revolution of 1917, Moscow became the seat of power of the Soviet Union, a fiercely Communist regime.

But over the course of the late 20th century, Lenin's idealistic revolt against inequality had slowly eroded, bringing about an end to the Soviet Republic in 1991.

Since then, the city has raced towards a capitalist future with reckless abandon.

With ambitions as colossal as the buildings that surround them, there as many billionaires here as there are in New York City, and four times as many cars.

Luckily, Muscovite commuters have an alternative.

Established in 1935, the Moscow Metro spans more than 330 kilometers beneath the city proper, making it one of the longest in the world.

It's also one of the most stunning.

Designed to reflect the radiance of the Soviet Empire, the stations are more akin to art galleries than train lines.

Adorned with frescoes, marble columns and chandeliers, these tunnels are used by an astounding nine million commuters every day.

That's more than London and New York's undergrounds combined.

Despite its modern facelift, reminders of the Soviet era remain scattered throughout the city.

None more potent than the Kremlin.

Sitting on the bank of the Moskva River, it's served as the seat of power for autocratic tsars, Communist dictators, and pin-up presidents alike.

The Kremlin dates back to the 11th century, though much of the complex as it stands today was designed by the Italians during the Renaissance Period.

It includes no fewer than 20 towers, five palaces, four cathedrals, an armory, and the modern addition of a helipad.

(upbeat operatic music) Right outside the Kremlin is Red Square, the cobblestone beating heart of Moscow.

Once the city's great marketplace, it now plays host to all manner of public events, presidential inaugurations, to New Year's Eve celebrations and concerts.

Of all the landmarks in Moscow, the most readily recognizable would have to be St.

Basil's Cathedral.

Shaped to mimic the form of a flame of a bonfire, it was commissioned by Ivan the Terrible in the mid-16th century to commemorate a great military victory over the Kazan, a kingdom ruled by the grandsons of Genghis Khan in modern-day Bulgaria.

Originally a Russian Orthodox church, St.

Basil's was confiscated and secularized by the Communists in 1929, and remains the property of the Russian Federation to this day.

(gentle music) A more recent landmark is the Memorial Museum of Cosmonautics, a monument to the Soviets' achievements in space exploration.

A throwback to the space race of the Cold War era, the museum honors trailblazing cosmonauts like Yuri Gagarin, the first human in space, and the groundbreaking efforts of the Soviet space industry which accomplished technological feats that changed the world as we know it.

An essential element in modern telecommunications, satellites are today taken for granted.

But it wasn't so long ago that Sputnik, the first man-made satellite, made its pioneering journey towards the stars, elevating humanity into a new era.

Today, as Russia tries to reassert itself on the world stage, Moscow is once again on the rise.

But by generating intrigue and controversy along the way, for this seat of power, it may be a bumpy ride.

(dramatic music) Revered by the sons and daughters of Egypt as The Mother of the World, Cairo is a city like no other.

For much of the global community, Cairo's many exotic landmarks are the stuff of myth and legend.

But for the 22 million people that call this city home, these World Heritage-listed sites are simply part of the everyday landscape.

Arguably the most recognizable city in the Middle East, Cairo is also the largest.

(uptempo Mediterranean music) Famously dwelling along the banks of the River Nile, the lifeblood of the city since the dawn of history.

Many consider this part of the world to be the cradle of civilization, the birthplace of writing, where irrigation, farming and animal husbandry were first practiced.

And where, for better or worse, taxes were first introduced.

But for most, Egypt is instantly recognizable as the home of the Great Pyramids of Giza.

Not so long ago, these ancient monuments stood in isolation amongst the desert dunes, but today, Cairo's rapidly expanding urban sprawl threatens to consume them.

While a visit to these historic ruins sits atop many a jet setter's bucket list, for these locals, it's simply their backyard.

The largest and oldest of the three pyramids of Giza and one of the original Seven Wonders of the World is the Great Pyramid of Khufu.

The other two in the trio were built by Khufu's son and grandson in turn.

As one of the few man-made structures of the ancient world visible from space, the dimensions of these monuments are dazzling.

Khufu's pyramid alone is the size of more than four city blocks.

It contains 2.3 million individually placed stones, each weighing as much as 27 tons.

An epic feat of engineering that to this day defies belief.

Shrouded in mystery, the Great Sphinx is no less impressive, measuring nearly 73 meters long and over 20 meters high, the statue was carved from a single block of limestone around 12,000 years ago.

Contrary to popular belief, Napoleon did not shoot off its nose.

While Cairo's outer limits are more intriguing than those of most cities, the urban center is not without its charms.

Many of the treasures recovered from inside the pyramids are now housed in the Museum of Cairo.

With 120,000 items, the collection is extensive.

There are statues, tablets, and sarcophagi as far as the eye can see.

(upbeat Mediterranean music) While there is plenty to do and see in the inner city, getting around is not so easy.

As is the case in so many other mega cities around the world navigating Cairo's traffic is challenging, to say the least.

In peak hours, it's bumper to bumper.

The city is struggling with the social and environmental implication of intense overcrowding.

And with its economy in full swing, the city's rapid growth shows no signs of abating.

As one of the planet's oldest cities moves towards the future, the challenges before it are numerous.

Perhaps the greatest, maintaining the balance between historical preservation, and effectively modernizing an aging infrastructure for a rapidly growing population, ensuring that future generations enjoy not only the perks of modern life, but the cultural wonderments that have awed and inspired the people here for thousands of years.

(dramatic music) (mysterious music) This is Lima, the blossoming capital of Peru.

It's the third largest city in the Americas.

But wedged between the Pacific Ocean and the Andes Mountain Range, this mega city is fast running out of growing room.

Born of a collision of cultures, Lima is a city with deep roots.

Originally home to the mighty Incan Empire, the lands upon which Lima now stands were conquered by invading Spanish Conquistadors in the mid-16th century.

The capital's population surged from just over half a million in 1940 to almost five million by 1980.

Lima expanded so rapidly and so organically that the concept of sustainable urban development was seemingly lost along the way.

As a result, today, more than a third of its 10 million inhabitants live in makeshift shantytowns known as Barriadas.

Nevertheless, it's a highly functioning town that shows little sign of slowing down.

The center of downtown, Centro Historica De Lima is a UNESCO World Heritage site, and it contains many strong reminders of the past.

Within it, the Plaza Mayor contains all of the city's most important buildings grouped around a square, a quintessentially South American arrangement.

It's here that the Municipal Palace, the Palace of the Union, and the Cathedral of Lima are all located.

This quaint pueblo village community layout has been maintained, despite hundreds of years of urban growth.

Reminiscent of its British counterpart, the bombastic changing of the guards ceremony at Government Palace is a sight to behold.

(boots thudding) Today, Lima is a Catholic city, and its places of worship attract huge crowds.

None more so than the Church of San Francisco, and the St.

Francis Monastery.

Some of the texts in the library predate the monastery itself, having traveled with priests from Spain shortly after the conquest of the Incas in the 1530s.

Of equal cultural importance are the impressive catacombs.

Centuries ago, cemeteries were established under many of Lima's churches.

As many as 75,000 Christian souls are estimated to be entombed under this one alone.

Around the city, there are also several sites held sacred by indigenous peoples.

30 kilometers south, Chauchilla Cemetery was an important burial site for the ancient Nazca culture between the third and ninth centuries.

The dry climate of the Peruvian Desert, preserving bodies that have sat here, facing the rising sun for hundreds of years.

Older still are the ancient geoglyphs known as the Nazca Lines.

Created between 500 BC and 500 AD, these mysterious zoomorphic figures can only really be appreciated from the air.

Amongst the more well-known designs are the monkey, hummingbird, and spider.

Created by digging shallow lines in the earth, there is still much scientific debate surrounding their purpose.

Perhaps nothing better represents the symbols of Lima's past and present than Huaca Pucllana.

The ruins of this ancient pyramid reside amongst one of the most affluent areas of Lima, Miraflores.

Today, most of the city's ancient structures have succumbed to the ravages of time, giving way to the eclectic modern face of Lima in the 21st century.

A mega city growing faster than perhaps it should, Lima faces many challenges.

But if there is one thing that this great city has proven in the past, it's that it has the capacity to overcome adversity as it strives for a better future.

(dramatic music) (upbeat music) Our last mega city in the making is known by a number of names; The City of Angels, La La Land, Tinseltown, and the City of Dreams.

But it's best known around the world simply by its initials: LA.

Founded in 1781, Los Angeles is the financial, commercial, and of course, cultural capital of California.

After New York, it's the second most populous city in the United States.

While its metropolitan area is home to more than 13 million residents, LA itself hosts almost four million within its city limits.

It's also one of the most multicultural cities in America.

Attracted to the bright lights and the promise of a better life, people flock here from all corners of the globe.

Also known as the City of Dreams, it may come as no surprise that Los Angeles is a distinctly media-driven town.

In fact, one in six of the city's four million residents pursues one form of artistic career or another.

Not the least, LA is home to the oldest film industry on Earth.

It all started when a curious Cecil B. DeMille hired a barn on the edge of town and began experimenting with the emerging art form of motion picture.

From these humble beginnings, LA's film industry has grown into a world-renowned cultural and economic powerhouse, home to icons such as the Academy, and Golden Globe Awards.

Today, LA's film industry is worth over 500 billion dollars a year.

(hard rock music) Together with other key creative industries such as music, TV and advertising, the city's artistic types generate close to a trillion dollars annually.

So synonymous is this city with show business that one of its suburbs has become a virtual brand for the industry: Hollywood.

Built in the 1940s to promote a major real estate development, the Hollywood Sign has become an enduring symbol of the cult of celebrity, and a beacon to those in search of fame and fortune.

Those that have already made it to the dizzying heights of stardom are immortalized on Hollywood's Walk of Fame.

And frequent A-list hotspots such as Grauman's Chinese Theater, a popular red carpet venue for world premiers of major league films.

(upbeat bright music) Featured in countless Hollywood movies, many of the city's neighborhoods have become household names the world over.

Punctuating Route 66, Santa Monica is where you'll find that stretch of sand made famous by the babes of Baywatch.

Venice is home to that instantly recognizable beach-side promenade.

And Beverly Hills has that most famous of zip codes, 90210, in which many a celebrity has resided; Frank Sinatra, Jimmy Stewart, Ellen DeGeneres, Charlie Sheen, and Lionel Richie, just to name a few.

Unlike most of the mega cities in the world, LA doesn't laud its CBD.

And though high rise buildings dominate the skyline in the downtown area, most Los Angelites prefer to live in houses.

Even if that means moving away from the center of town into the San Fernando Valley.

One trait that LA does share with a host of other mega cities is its traffic.

The people of LA love their cars.

Unfortunately, when there are several million like-minded people in a city, things can get a little congested.

But life isn't always about reaching the destination.

Sometimes it's more about the journey.

And true to form, even the streets of LA can provide some welcome distractions.

Rodeo Drive is renowned for its shopping, while Mulholland Drive, the windy route into the Hollywood Hills, showcases the homes of the uber rich and famous.

And of course, there's Sunset Boulevard.

Immortalized in pop culture, it stretches from downtown LA to the Pacific coastline.

With great breaks and a strong beach culture, Los Angeles is a mecca for surfers.

While some simply enjoy getting amongst the waves, others take the sport more seriously.

More pro surfers come out of LA than any other city in the world.

Supported by the likes of the Beach Boys, and the Red Hot Chili Peppers, this wave-riding subculture has spread beyond California, and has found its way into the psyche of young people around the globe.

(upbeat rock music) Indeed, there are few cities that have penetrated the hearts and minds of people the world over as successfully as LA has.

Constructed with smoke and mirrors, it's a mega city driven by movers and shakers, and inhabited by the rich and famous.

For this dream machine, the show just keeps getting bigger and grander.

The largest urban enclaves on the planet, mega cities are dense, eclectic, and chaotic.

But amidst the noise and confusion, there's an unwavering sense of potential.

Home to tens of millions, they are creative hives, social mavericks, and cultural icons.

More than the sum of their parts, their unique histories, rich traditions, and wealth of human spirit have transformed these heaving megatropolises into some of the world's greatest cities.

(dramatic music)