James Stewart

In amongst these, he came across a single vertebra, strange looking and enormous.

Based on its size alone, it was labelled as a croc.

But Hastings knew instantly that something was different about this one.

This was not a crocodile at all.

So he showed it to his lab partner, Jason Bork, who agreed.

That's a snake, he said.

But this was not like any snake the world had ever seen.

Bork raided the university's fossil collection, pulling out the closest looking vertebra he could find, that of an anaconda.

It wasn't a perfect match, although it looked quite similar.

The only problem was the anaconda vertebra was three times smaller than the new fossil they had just received.

How could a snake be this big?

Surely it just wasn't possible.

They needed more evidence.

They sent word back to the team on the ground in Columbia that more specimens were needed, specifically of fossilized snakes.

Eventually, the team collected 100 snake vertebrae from nearly 30 individual gigantic snakes.

Now the most amazing part about all this is that Jonathan Block himself had also been sifting through specimens over the last couple of years, and he had also received giant vertebrae just like this one, but even someone with his expertise had totally dismissed them.

He said it's like someone handed me a mouse skull the size of a rhinoceros and told me that's a mouse.

It's just not possible, except now he realised that it was.

The only problem was they had no idea what kind of snake they were dealing with.

Realising what was at stake, Block called Jason Head, then at the University of Toronto, the world's leading snake expert at the time.