This past fall,

fall 200 people gathered at the Explorers Club in New York City.

The building was once a clubhouse to famed naturalists and explorers.

Now it's an archive of ephemera and rarities from pioneering expeditions.

From treks to the world's tallest mountains, the North Pole, and the Moon.

Woolley Mammoth Tusk's frame a fireplace, a menacing polar bear towers near the landing

with claws at the ready, and a cheetah rumored

to have been shot by Teddy Roosevelt sits on a plinth just upstairs.

The gathering was in honor of a new expedition.

One in search, not of a single animal, but of thousands.

Best reporter Caitlin Swaljay.

The club was hosting a biological census, an ecological survey so difficult, so complicated, so taxing,

that it had never been attempted before, and may never be attempted again.

It is a really big project.

Like, I don't think we've ever been involved in a project of this scope in our lives.

It's like moving a small little army around.

This is Jamie Allen.

The census was his idea.

And when he started, it was a small operation.

But now Jamie is merely the tip of a vast pyramid of census-related personnel,

including a logistics chief, a chief cartographer of veterinarian, an epidemiologist, a specialist from the Fish and Wildlife Service, and of course, a web team.

And that's just the core staff.

...