In the early 1920s, a fossil hunting team  from the American Museum of Natural History   working in the Gobi Desert was disappointed to  report that they’d discovered dinosaur remains.

While most paleontologists would  consider this a massive success,   to these researchers, the  fossils represented a failure.

Because they hadn't been trying  to find dinosaurs at all… They’d actually been searching  for fossils much closer to home   instead - fossils of the earliest humans.

And those dinosaurs only showed  that they were looking in the   wrong place and in the wrong geologic time period.

Meanwhile, other people were also hunting for  a singular so-called ‘cradle of humankind’   everywhere from Europe, to the islands of  Southeast Asia, to imaginary lost continents.

And the reason they were all over  the map – literally – was because,   at the time, scientists had no idea  where to look for ancient humans.

They just had no clue where humanity had begun.

And it would take decades before they realized  that maybe there wasn’t just one cradle.

Maybe they’d been asking the  wrong question all along.

Today, humans are pretty much everywhere,  on every single continent worldwide.

And this basic fact that we take  for granted raises a unique problem.

See, when Charles Darwin published  On The Origin of Species in 1859,   he predicted that evolution by natural  selection would eventually shed light   on human history and uncover  the details of our origins.

But there was no “light” yet – no fossil evidence  of human evolution that was widely recognized.

So when it first occurred to scientists to  start looking for the fossilized remains   of our ancestors, they had to  guess where they should look.

And they had no hints to go on.

Other primates,   like chimpanzees and gorillas for example,  are found in more restricted areas.

Or, at least, on a single continent: Africa.

So a search for the fossils of their  ancestors should probably begin in Africa.

For orangutans, the same would be true for Asia.

But for us, it’s messy.

Because we’re  everywhere, the question was wide open.

Where did our lineage evolve  after diverging from our common   ancestor with chimps – which we now know  happened about 6 to 7 million years ago?

Early on, some scientists theorized that  our lineage might have originated in Asia.

One German zoologist even hypothesized that humans   had evolved on a now-sunken continent  in the Indian Ocean, named Lemuria.

This imaginary place stretched from the  south-eastern shores of Africa, toward   India and Indonesia to the east, and would’ve  once been connected to land via a land bridge.

It was supposed to have been a tropical “paradise”  that would have allowed human ancestors to evolve.

But Darwin disagreed.

He thought our  origins were located in Africa because   of our similarities to chimpanzees and gorillas.

And in contrast to the paradise idea, some  advocates for an African origin argued that,   actually, the harsh environment of South  Africa was the catalyst for our ancestors   evolving our human-like features, like big brains.

Environmental challenges and the presence of  dangerous predators - not paradise - led to us.

Now, it’s worth noting that there  were other perspectives on this topic.

Many cultures around the world had  - and still have - their own origin   stories that differ from the ideas  of these early western scientists.

And the western scientific debates were often   built on false assumptions about race  and superiority - a problematic theme   in the science of human origin that  still rears its ugly head even today.

The colonial history of this field of science  is why local people in Africa and Asia were   often deliberately prevented from contributing  to the research taking place in their own lands.

Instead, they were pushed out by westerners who   centered the debates around their  own fossil finds and perspectives.

And, ultimately, those old-timey  guys were just speculating.

In fact, Darwin even said it was “useless to  speculate,” because a long time had passed   since our origins, giving plenty  of time for migrations to happen.

But others speculated anyway.

And by the 1880s, some began acting on those  speculations – including a Dutch anatomist,   Eugene Dubois, who traveled to Sumatra  and Java to hunt for our origins.

This search resulted in the Java Man  fossils, now known as Homo erectus.

And over the next few decades, a series  of skulls from the site of Zhoukoudian,   China, found by scientists like Pei  Wenzhong, added more evidence for Asia.

But competing discoveries from  Africa and even Europe emerging   around the same time left the question wide open.

It wasn’t until the second quarter of the 20th   century that fossils started to  accumulate to suggest Africa.

One of the most important of these is  a fossil skull of a juvenile hominin   discovered in 1924 in South Africa,  dating to around 2.8 million years ago.

Known as the Taung child, the find is among the  first early human fossils discovered in Africa,   and it helped the idea of an African origin for  our lineage become widely accepted by the 1950s.

Since then, we’ve found many other fossils of  potential long lost African relatives dating   to either side of the Taung child  on the timeline of human evolution.

For example, now we know about  Sahelanthropus, Orrorin, and Ardipithecus.

They’re all very early potential hominins  that date to around or shortly after our   divergence from our common ancestor with  chimpanzees, some 6 to 7 million years ago.

And around 4 million years ago, the genus  Australopithecus appears in Africa, too,   which includes upwards of eight  species and encompasses specimens   like the Taung child as well as the famous Lucy.

Many australopithecines have  also been found more recently,   including finds nicknamed Lucy’s  great-grandfather and Lucy’s baby.

It was this genus that eventually gave rise to our  own, Homo, sometime around 2.5 million years ago.

And it was members of that genus, specifically  Homo erectus, that seem to have first migrated   out of Africa by about 2 million years ago,  eventually spreading to much of Eurasia.

So Darwin, it seems, had been right all along.

But while there's been very little doubt for  decades now that our lineage and genus both   emerged in Africa, the question of where our  species emerged proved much harder to pin down.

Because, earlier members of our genus  made it to Eurasia well before we Homo   sapiens are thought to have first  appeared, around 300,000 years ago.

So could a population of hominins  have birthed our species,   Homo sapiens, in Eurasia rather than Africa?

This question was wide-open throughout the  late 20th century and into the early 21st,   with two competing hypotheses taking center stage… One was called the Multiregional Hypothesis.

And like the name suggests, the basic idea is that  after hominins radiated within and beyond Africa,   different populations in different places  regularly came into contact and interbred.

This kept them all very similar by mixing their   various traits into the cocktail  that we now know as Homo sapiens.

Which would mean that our species  emerged not in one time and place,   but gradually across multiple continents.

In contrast, the Out of Africa model  proposed a very different story.

It argued that we can trace our species' origin  to a single time and place, somewhere in Africa,   only expanding beyond that continent once  we were already fully-fledged Homo sapiens.

The debate over which of these  ideas was correct raged for decades,   only really becoming clear  in the last 30 years or so.

The genetic evidence showed that we can, indeed,   trace the initial origins of our  species to the African continent.

For example, it is now well established  that the vast majority of human genetic   diversity today exists in  modern African populations.

And this is telling because it  suggests that people who are not   African are descended from only a small  group of people who left the continent,   taking just a fraction of the  total human gene pool with them.

Scientists call this a population bottleneck.

So, in some ways, the Out of  Africa hypothesis was correct.

But the genetic evidence also shows that,  when ancient Homo sapiens left Africa,   they interbred with our cousins the  Neandertals and Denisovans in Eurasia.

And because the Out of Africa  hypothesis originally argued   that Homo sapiens replaced other  populations rather than interbred   with them, this means aspects of the  multiregional model were right, too.

To make things more interesting, it turns  out that the Out of Africa migration around   60-to-80 thousand years ago was just one  of many – though it was the only one that   clearly left direct descendants,  who are still all over the world.

But even knowing that Homo  sapiens are from Africa,   we are still left with at least one big question… If the cradle of humankind was indeed in  Africa, where exactly on the continent was it?

After all, it’s a vast and ecologically  diverse continent - spanning thousands of   miles and containing everything from  deserts to savannas to rainforests.

So where exactly is our childhood home?

Well, in just the last few years,   scientists have begun to realize that  this may be the wrong question altogether.

Because a series of recent studies using  DNA from both modern and ancient people,   as well as archeological  and environmental evidence,   have begun to paint a much more  complex picture of our African origins.

One where we didn't actually evolve in  one single population in one single place… Instead, we can trace our  emergence to multiple ancient   populations that were scattered across Africa.

When environmental conditions allowed, they  occasionally met up and mixed their genes,   all contributing directly to the eventual rise  of us ‘modern’ humans, some 300,000 years ago.

There was no single cradle, it  was a continent-wide playpen!

And instead of thinking about our  origins like a tree with a single trunk,   perhaps the more accurate view  is a complex braided stream… An intertwined story of migrations,  transitions, and exchanges between   various ancient populations that  unfolded over vast time and space.

No human is an island, and it turns out that this  has been the case since our very earliest days.