[Narrator] They're born of violence and uncontainable rage... opportunists who take advantage of a weak spot in the Earth's surface, making an explosive entrance into the world.

And the tantrums only continue, building themselves up while bullying those around them with their unpredictable outbursts.

But over time, many mellow with age.

And in the wake of the drama and destruction, the elements sculpt something unexpectedly lush from the molten lava.

So breathtakingly beautiful that we've come to know them as the world's greatest volcanic islands.

♪ This is the world's largest mountain range.

Its highest peak dwarfs terrestrial summits, even that of Mount Everest.

But most of it is hidden from view, deep beneath the sea.

Millions of years ago, volcanic activity pushed the Hawaiian Islands out of the North Pacific, creating an archipelago that continues to expand today.

The most potent contributor to its current growth is Mount Kilauea.

Hundreds of thousands of years since first emerging from the sea, she's the most active of the five volcanoes that make up the largest landmass of Hawaii.

The Big Island was a slow starter.

It was the last of the group to form but has made up for lost time, growing to almost double the size of the other seven Hawaiian islands combined.

In 2018, after lying relatively dormant for 35 years, Kilauea awoke, and she was angry.

Lava flows and toxic gasses laid siege to nearby towns, but the much greater threat of explosive eruptions still hangs over the heads of the island's residents today.

While Kilauea still bubbles and hisses, her most destructive show was more than 200 years ago, when at least 5,000 people were killed by molten projectiles and lava.

But she pales in comparison to her larger neighbors.

Mauna Kea is three times the height of Kilauea but has been dormant for thousands of years.

Her summit is now used as a private observatory.

Mauna Loa is considered the largest land-based volcano on earth.

She's still active, but without the force or fireworks of her more famous friend.

She managed to capture the attention of NASA in the 1960s, which trained its astronauts for lunar walks on the hardened lava fields around her crater.

But today, it's the action that captivates most visitors, the moment Kilauea's molten rock flows into the ocean, enlarging the Earth a piece at a time.

The volcanic past of the Hawaiian Islands is obvious throughout the group, but the original Polynesian settlers had a different explanation for its creation.

They credit the demigod Maui with fishing the islands from the sea with his large hook made from the jawbone of his grandmother.

A combination of wind, waves, and wings brought life to this rocky outpost, far removed from the rest of Polynesia.

The earliest inhabitants are thought to have traveled from the Tahitian Islands as far back as the fourth century.

They established a complex tribal structure of worship and sacrifice, dictated by a code of conduct known as kapu, and ruled over by local chiefs who were thought to be closely connected to the gods.

When Captain Cook first arrived in 1778, his appearance caused quite a stir.

His ships were thought to be floating islands and the British explorer deemed to be a deity, since he'd turned up midway through a festival to honor Lono, the god of peace.

Unfortunately, the goodwill didn't extend to his second visit, when it was discovered Cook had taken some wooden idols from a local temple.

A fight ensued ending in the death of the great explorer and four of his marines, but this didn't deter the influx of foreigners intent on discovering for themselves the exotic land in Cook's writings.

They brought with them new crops, ideally suited to the tropical volcanic soil.

Pineapples, in particular, flourished in the Hawaiian climate, at one stage producing 75% of the world's supply.

But the successful production meant importing labor to keep up with demand.

Chinese workers brought diseases to the remote islands and, combined with ongoing tribal unrest, wiped out half the population in the early 1800s.

By this time, King Kamehameha had united the eight main islands of Hawaii, and he and his successors ruled until America annexed the archipelago at the end of the 19th century.

The United States set up a naval base on the island of Oahu to help protect their whaling and business interests in the Pacific.

Pearl Harbor became infamous in December 1941 as the site of a surprise Japanese attack on the U.S.

Pacific fleet.

More than 2,300 people were killed, and 1,100 injured in the aerial bombardment which damaged much of the fleet and sank four battleships.

Almost 200 aircraft were also destroyed.

In a state of shock, America entered World War II the following day.

[Franklin Delano Roosevelt] A state of war has existed between the United states and the Japanese Empire.

[Narrator] A memorial has been built over the top of the wreck of the "USS Arizona," attracting more than a million visitors annually, but that's just a fraction of the total number of tourists who come to Hawaii every year.

For more than a century, the island group has been a popular travel destination.

But it's not just the climate and culture bringing the visitors in.

Hawaii is the undisputed home of surfing.

Polynesian kings were rumored to have ridden waves on planks of wood back in the 1800s.

But the sport gained global recognition when Olympic swimmer Duke Kahanamoku started to surf the swell in Oahu at the turn of the 20th century.

The archipelago's isolation means it's at the receiving end of big ocean swells, unbroken in their journey across the Pacific.

And when they do reach the shore, the result is truly terrifying.

The most famous break is the Banzai Pipeline, which is known to have claimed at least a dozen surfers and injured many more over the past 50 years.

But the devoted say it's being at one with the waves that makes the risk worthwhile.

It's a common theme around the islands where culturally, nature is considered sacred and animals act as guardian spirits, guiding and protecting those who enter their domain.

There's something otherworldly about Hawaii.

Away from the crass commercialism of the major cities is a land of soaring cliffs, ancient valleys, and hidden highlights.

And while much of the planet is slowly sinking, or being worn away, here it's still forming, still sculpting the shape of things to come.

♪ It's a land of extremes born of fire and ice, caught between heaven and hell at the northern extremity of our planet.

Millions of years old but still beholden to Mother Nature's violent whims, Iceland is the home of volcanoes, 130 in total spread over the island nation... the result of its precarious placement on the top of two tectonic plates.

30 of the mountains are still active, and while no one has ever died here as a direct result of the explosive environment, the fallout from the fumes has indeed been lethal.

In the late 1700s, half of Iceland's livestock died from poisonous volcanic gases, causing a famine which killed almost 10,000 people.

But the devastation was felt more keenly further afield.

The sulfur dioxide released into the atmosphere spread across the Northern Hemisphere, destroying crops and resulting in the deaths of up to six million people.

Even in modern times, Icelandic volcanoes can still bring Europe to a standstill.

Massive ash plumes in 2010 and 2011, brought air travel across the continent to a halt, as the cloud swirled 20 kilometers into the atmosphere.

But the impact on the ground was even more devastating.

The first volcano was buried 200 meters under a glacier.

The Skaftá River valley south east of the capital Reykjavik bore the brunt.

An estimated 400,000 liters of melted water per second was released as the glacial ice was decimated by the volcanic blast.

Millions of tons of ash mixed with the flow to leave the once lush landscape with a desolate, drab coating.

The following year, another explosion from a different volcano, this time, fracturing a glacier on one of Europe's largest icecaps.

Vatnajokull covers almost 10% of Iceland and is visible from space.

The eruption widened the already large lake system in the national park, a body of water that's been steadily increasing in volume since the 1930s.

But it's not just volcanic activity that's caused the glaciers to retreat.

A rise in surface temperatures has seen the lake quadruple in size in the past 50 years.

Icebergs and delicately etched caves are the only reminders of the thick blanket of ice that once covered this area.

Despite its chilly exterior, Iceland's heart of fire has a habit of breaking through all over the country.

Surface water, working its way down through cracks and crevices to the bubbling magma, quickly boils, and, under pressure, shoots back up in a spectacular display.

The term geyser comes from an Icelandic word meaning to gush.

The phenomenon was first noticed here hundreds of years ago and gained the attention of scientists across the globe.

The so called Great Geysir has been active for 10,000 years and has been measured shooting 40 stories into the air.

The neighboring Strokkur geyser is less intense, but its eruptions are more frequent, occurring every few minutes.

♪ The Icelanders have seen the value of their abundant supply of geothermal energy, harnessing it for everyday use.

30% of the island's electricity and almost 90% of its heating comes from its natural underground source.

Warm water is sent along a 27-kilometer network of pipes from the power plant to the capital.

The resource is so plentiful, even some of the footpaths are heated in Reykjavik.

But these creature comforts are a far cry from the frigid coastal waters that surround the island.

Ever since the first Vikings landed in Iceland in the ninth century, fishing has been a major part of life here.

Controversially, marine mammals are still targeted in the catch, including the endangered fin whale.

Tourists are amongst the biggest consumers of whale meat, the demand for which is matched equally by the desire to see them in the water.

100 years ago, fishing made up 90% of the island's income.

And while tourism has reduced the impact of fishing on the economy, it's still considered an important part of the country's heritage and figures heavily in folklore.

According to legend, these rocky sea stacks off the island's south coast are the remains of trolls who tried to pull ships to shore but failed in their endeavors, turning to stone when the sun rose.

In reality, they are basalt formations, the end product of lava thrown out by volcanoes which has condensed and solidified.

The nearby black sand beaches of the small fishing village of Reynisdrangar are a more refined product of the magma projectiles whose reach appears to know no bounds.

The so-called troll toes are home to thousands of nesting puffins and have been sculpted by the dramatic shifts in tide the area is renowned for, the more likely culprit behind the demise of fishing vessels.

For a large island of over 100,000 square kilometers, Iceland's volcanic past and present have permeated virtually every landscape across this country.

And while its interior continues to be molded by its fiery outbursts, its coastal region also gives away its explosive side.

Beyond the icy exterior lies a land with a heart of fire, a volatile nature which has the ability to both harm and help its people.

♪ The spiritual and physical are closely interwoven on the Indonesian island of Bali.

In this largely traditional province, every element of nature has a link to the deities and keeping them on side is a matter of priority.

So it's hardly surprising its most fiery feature is also its most sacred.

Mount Agung is Bali's highest peak and its chief trouble maker.

At over 3,000 meters high, it's large enough to influence climate, drawing moisture from the clouds moving in from the fertile west, leaving the east of the island dry and barren.

But it's more about what it could do that makes scientists nervous.

They rate Agung as one of the world's most likely contenders for a major eruption in the next 100 years.

This active volcano is part of the so-called Pacific Ring of Fire, an area of fault lines in the Earth's crust responsible for 90% of the world's earthquakes and all but three of the largest eruptions in the past 12,000 years.

Most of the time, Agung's bark is worse than its bite.

In 2017, it threw massive ash clouds up to 4 kilometers into the atmosphere, shutting down air traffic to this popular tourist destination, but no lava and no loss of life.

Half a century ago, it was a different story.

The mountain blew its top in spectacular style, shrinking in size by 200 meters as it cascaded molten rock down its sides.

At least 1,500 people were killed when villages were swamped by the flow.

Bali's most important temple lay in the path of the lava, but locals believe divine intervention saved the Pura Besakih from certain destruction.

The thousand-year-old structure was missed by a matter of meters... and today is still the most revered place of worship for the island's large Hindu population.

In the midst of a Muslim country, Bali is a Hindu haven.

More than 80% of the population follows the faith here, which was brought by traders from India close to 2,000 years ago.

It blended well with indigenous beliefs, honoring animal deities which are still practiced today.

Its impact on Bali shouldn't be underestimated.

Away from the coastal enclave of tourists, spirituality features strongly in this largely agricultural existence.

The World Heritage-listed Subak irrigation system has its principles based on Hinduism.

The complex, terraced paddy fields were first trialed for rice growing 1,200 years ago.

Farmers were intent on honoring the source of their water supply, building shrines and temples over natural springs where they could offer gifts of produce to satisfy the spirits.

In addition to the monuments, a series of canals, tunnels, and weirs were constructed to gently guide the water on its most beneficial path.

The system is fed by a crater lake housed in another Balinese volcano, but this one is not as volatile as Agung.

Mount Batur is, in fact, more active than its infamous neighbor, but its eruptions are nowhere near as powerful.

Although traditional ways still persist here, customs and culture are being tainted by the more than five million visitors who converge on Bali every year.

Tourism now supports 80% of the economy.

And while the income has helped the struggling island, the environmental impacts have been pronounced.

The huge demand for reliable natural resources by the upmarket resorts has meant half of the island's 400 rivers have dried up.

Rubbish in the waterways is another major concern.

Indonesia is one of the world's worst polluters, producing 10% of the planet's plastic waste.

It's an ongoing battle, and the stakes are high not only for Indonesian waters but for marine systems much further afield.

Bali has close to a thousand different species of fish and more than 500 types of reef-building corals, seven times as many as the entire Caribbean.

Historically, this area has populated much of the Pacific Ocean with currents carrying the coral larvae to Vanuatu, Fiji, and beyond.

Not to mention, the offshore waters have long been a source of food for the locals.

The wave of human visitation is threatening the delicate ecosystems the Balinese have worked so hard to cultivate.

But the biggest danger looms over locals and tourists alike, the outspoken mother mountain.

And no amount of prayer, prostrating, or peaceful practice is likely to prevent her from having the final word on Bali's future.

♪ There is a Maori legend that says when a great priest first walked the newly created land of Aotearoa, he called upon the fire demons of the underworld to keep him warm.

So they conjured up Whakaari, or White Island as Captain Cook later called it, a volcano off the Bay of Plenty in New Zealand's north.

Today, scientists tell a more down to earth, but no less dramatic story of the island's creation.

They believe the cone was built up over 150,000 years by continual volcanic activity.

And what can now be seen is just the tip of a much larger submarine mountain, which descends 1,600 meters to the sea floor.

It's easy to see why the original inhabitants viewed the island's most dramatic feature with such reverence and awe.

Whakaari is known for its effusive eruptions in which lava steadily flows onto the ground rather than producing fiery explosions of magma.

But it occasionally reveals its more fearsome side.

Major eruptions in the early 1980s scorched the earth, wiping out extensive forests to produce the desolate landscape we see today.

In the wake of these eruptions, a simmering lake was formed in the volcano's crater.

90 meters deep, it's filled with rainwater that, over time, has seeped into the ground creating an uneasy tension below the surface which inevitably reaches boiling point.

Steam vents, known as fumaroles, are scattered around the island releasing a mixture of gases at a sizzling 400 degrees Celsius.

While water vapor and carbon dioxide are the largest compounds in these emissions, there's also a minor element, one which has made a major impact.

Sulfur crystallizes when it reaches the surface, transforming it into a valuable commodity.

The Maoris of mainland New Zealand have long recognized the horticultural benefits of using sulfurous crystals as a fertilizer, believing it to be a gift from Rongo-ma-Tane, the god of cultivation.

Historically, they'd make the day-and-a-half journey across the sea in canoes to collect the minerals to help boost their crops.

And seeing the Maoris' success, European settlers soon followed suit.

But these miraculous crystals had more to offer subsistence farmers.

Before the discovery of antibiotics, sulfur was also used as an antibacterial agent in medicines, and to make match heads and sterilize corks, surely a gift from the venerated gods below.

As demand for sulfur grew, a small mining operation was set up in the late 19th century but came to an abrupt halt in 1914, when the western part of the crater collapsed, sending a swift and destructive mud flow through the camp.

All 10 workers were killed.

Only their cat survived, rescued by a supply ship several days later.

[Helicopter] Since the abandonment of the camp, the volcano has been turned into a site for tourism.

For visitors, the volcano offers a rare opportunity to stand inside a steaming caldera, or volcanic sinkhole, witnessing firsthand the sculpting of New Zealand.

The ability to study these geological processes up close has also drawn volcanic researchers to the site.

Scientists believe that Whakaari can act as an important early warning system.

Any seismic activity alerting them to possible eruptions of New Zealand's mainland volcanoes, which are influenced by the same tectonic forces.

Despite its constant state of flux, Whakaari is still an important breeding ground for 3,000 pairs of Australasian gannets.

It's thought that their accumulated droppings, known as guano, may have given Captain Cook the inspiration for naming this White Island.

80% of the Earth's surface, above and below sea level, has volcanic origins.

By closely studying these processes, we can learn important lessons about the formation of our planet, while acknowledging Maori mysticism was essentially correct in telling of a fiery force unleashed from the underbelly of the world.

♪ There's a volcanic island in the Indian Ocean that's historically struggled with its identity.

In the 500 years since it was first discovered, it's been named after a saint, a royal household, a famous military leader, and finally in honor of a peace settlement in France.

Just to add to the confusion, as a French territory, Réunion Island is actually the most far-flung member of the European Union.

It's certainly remote.

It sits more than 800 kilometers east of Madagascar off the southern coast of Africa.

But this is no tiny speck of an island.

Réunion's landmass covers more than 2,500 square kilometers, and its tallest peak is higher than any in Europe.

Piton des Neiges is an extinct volcano that helped create the island two million years ago.

Its massive crater and surrounding calderas, or sinkholes, dominate two-thirds of Réunion.

The remainder is claimed by the smaller but fiery Piton de la Fournaise, which is considered one of the world's most active volcanoes.

It's erupted more than a hundred times since 1640, and one of the most impressive outbursts was just over a decade ago.

In April 2007, La Fournaise sent a lava flow careening across the island at a volume equivalent to that of a thousand Olympic swimming pools each day.

The molten rock made it to the sea, clearing 45 hectares of land and part of the national highway along the way.

The flow was up to 60 meters thick in places and took several months to cool down enough for rebuilding to take place.

Volcanic disruption is an accepted part of life on Réunion, but in amongst the destruction, there are stories of miracles.

Islanders believe it was faith that saved the local church 30 years earlier from a similar fate.

When the lava reached the front door, the flow split in two, skirting around the building and leaving the church untouched.

This is an island used to dealing with the nuances of nature.

The eastern side of Réunion receives six times the rain of the west and has broken several world records for highest downpour.

Months before the big lava flow of 2007, it gained global recognition for a four-day deluge that dumped almost five meters of rain in the island's mountainous region.

That's more rain than Europe receives in an entire year.

The steep walls of the ancient calderas were well equipped to handle the influx, sending the excess to the rivers below.

[Helicopter] But these valley cliffs pose challenges of their own.

They're unsuitable for roads, so several mountain villages are only accessible by air or on foot along narrow and often precarious tracks.

The wet conditions and rugged landscape here have given rise to an abundance of native flora.

Réunion National Park covers 40% of the island and helps to preserve the more than 200 species of flowering plants found growing in its rich volcanic soils.

The Portuguese were the first to lay eyes on this fertile island back in 1507, almost 140 years before anyone settled here.

And they didn't come by choice.

The French government banished 12 mutineers to Réunion from the neighboring island of Madagascar in 1642.

20 years later, long after the exiled men had been returned to Europe, the French East India Company sent a dozen people to plant sugar cane on the island.

The crop grew quickly, beginning an industry that's still the mainstay of the economy today.

Labor was needed to work the plantations, so slaves were brought in from Mozambique and Madagascar.

But by the mid-1800s, slaves had been freed and replaced by indentured workers from China and India, who added to the island's cultural mix.

♪ The population now sits at more than 800,000, and fishing has become an important industry along with rum and vanilla exports.

Tourism is gradually building, but several fatal shark attacks in recent years has scared off many of the intrepid surfers that would otherwise make pilgrimage here in search of the perfect wave.

While the coastal communities have moved with the times, the mountain villages still cling to the cradle of their creation.

But it's the rambunctious volcano that ultimately calls the shots.

Hot-headed and unpredictable, she's capable of blowing her top at any time.

♪ There's an island group off Australia's east coast that's surprising in so many ways... lying hidden from humans until the late 18th century.

The discovery of Lord Howe Island was purely by chance.

A British naval vessel, "HMS Supply," spotted the island en route from Sydney to the penal colony on Norfolk Island in 1788.

But it was another 40 years before the first settlers set up shop as a supply station for the Pacific whaling fleet.

Lord Howe is surrounded by coral reefs, but sits nowhere near the tropics, and it looks more like a peaceful paradise than the remnants of an ancient volcano.

But this island is indeed the product of an underwater eruption close to seven million years ago.

It's typical of a shield volcano in that its watery lava spread out rather than piling up, leaving it largely low profile apart from a couple of obvious exceptions at either end.

Mount Eliza to the north and the twin peaks to the south retained enough molten rock to rise above the rest of the land.

The highest point is the tip of Mount Gower at 875 meters.

But according to scientists, Lord Howe is a mere shadow of its former self.

The sea and wind have eroded 90% of its original mass.

And given another 200,000 years or so, it will once again disappear below the surface.

But the water that's wearing it away has brought an unexpected bounty to the island group.

Situated 600 kilometers off the Australian mainland, Lord Howe has the most southern coral reef in the world.

But that just happens to be the perfect spot to catch the warm currents carrying replenishing coral larvae from the Great Barrier Reef, more than a thousand kilometers to the north.

Of the almost 500 species of fish found here, 60% are tropical... and 13 are endemic to Lord Howe's waters, part of the reason it's been given World Heritage status.

It's no wonder that tourism contributes greatly to the economy here.

But this idyllic island has limited visitor numbers to 400 at any one time in an effort to make sure the environment is kept in pristine condition.

Lord Howe is a relatively small island, just 10 kilometers long and barely two kilometers at its widest point, but its ecological footprint is much larger, as much of its natural heritage has been preserved.

Several species of plants and animals found here exist nowhere else on earth.

And the island's 350 residents are proud and protective custodians.

Bicycles outnumber cars, and mobile phones are non-existent.

It's a refreshingly simple way of life that has changed little in its 200 years of human occupation.

By the 20th century, word had gotten out about the island's many natural attractions.

And following the Second World War, visitors started coming by ship and seaplane, but not all arrivals made it safely.

In 1948, an Australian Air Force flying boat crashed into the hillside while attempting a nighttime landing.

Despite the heroic efforts of locals, seven of the nine crew lost their lives.

At the time, it was Australia's highest loss of military life outside of war.

There are 28 islands, islets, and rocks making up the Lord Howe Marine Park.

And towering above them all is Ball's Pyramid.

At 560 meters high, it's the tallest volcanic stack in the world and home to many of the hundreds of thousands of birds that flock to Lord Howe.

There are more than 200 species of sea and land birds here, many of which rely on these remote islands to breed, but history hasn't always been kind to the bird life that nests here.

Since the arrival of early settlers, nine native bird species have been declared extinct.

While the settlers' livestock decimated nesting sites, it was an unwelcome stowaway that proved most destructive-- rats.

These rodents were introduced when a ship ran aground in the early 20th century, and they've been a problem here ever since.

Steps have been taken to eradicate the egg-eating pests, hopefully preserving the vulnerable breeding colonies of sooty terns, which nest in the island's low-lying grasslands.

Lord Howe Island has shrugged off its volcanic past, evolving into a natural haven for the rare and endangered.

This compact island has blended the lofty, the low, and the lush into a desirable destination for all who seek sanctuary in the middle of the ocean.

♪ It's been called the Lighthouse of the Pacific-- the world's most accessible active volcano.

And for hundreds of years, it's been putting on a show.

The glow from the island of Tanna in southern Vanuatu, was enough to attract the attention of explorer James Cook on his voyage through the South Seas in 1774.

But for the locals, it's more than just a fiery freak of nature.

Tanna still has very traditional tribal values.

[Children speaking indistinctly] [Narrator] The local people at the base of Mount Yasur believe its smoldering inferno holds the key to their future happiness and prosperity while the villagers of Sulphur Bay are devoted to a deity they think lives deep within the volcano that overshadows them.

Entire villages here have turned their backs on outside influences, preferring to live according to ancient customs.

Medicine men are consulted instead of doctors, and children receive no formal education.

Instead, they get taught traditional skills that have been passed down through the generations.

It's a simple lifestyle, focused on resilience and self-sufficiency, virtually unchanged by government or missionaries over the centuries.

[Natives chanting] [Narrator] Many tribal rites and rituals still pay homage to the fiery deities that are believed to dwell within the island's volcanoes.

Visitors join villagers on the nightly pilgrimage to the rim, approaching via an extensive ash plain downwind of the crater.

Yasur is known for its Strombolian eruptions-- sporadic, relatively mild blasts that can, on occasion, turn into something truly terrifying.

In the mid-nineties, three people were killed by lava projectiles that unexpectedly shot up to a hundred meters into the air.

Today, the volcano's activity level is monitored and rated for safety.

If it's deemed too dangerous, the viewing area is closed until things settle down.

Yasur holds a deep spiritual significance for the local people and provides a steady stream of income, but the volcano has helped the island in more subtle ways.

The rich volcanic soil has produced a coffee bean crop which is highly prized throughout the Pacific and beyond.

Vegetation is lush on the island and rebounds quickly after devastating storms such as Cyclone Pam, which killed five people here in 2015.

Tanna's grass and bamboo huts stood little chance against winds of up to 250 kilometers per hour, leaving many of the 30,000 residents homeless and without safe drinking water.

But the people of Tanna are resilient and their needs simple, so the sea provided food where the land could not.

Tanna is an island seemingly lost in time.

Its people are perpetually sustained but also threatened by the volcano that's so central to their lives.

True to tradition, they venerate a formidable natural wonder they believe, in one way or another, contains the secret to happiness.

There's something mesmerizing about these mountains of magma standing tall and a little removed in the vast waterways of our world.

And try as we might to explain them through science or spirituality, there's still an element of mystery, an enticing mix of power and passion.

The world's greatest volcanic islands have been inspiring awe and respect since the dawn of human history.