In northwestern Peru, where the Amazon rainforest crashes into the Andes Mountains, there is one of the world's tallest waterfalls.

But until a couple of decades ago, the only people who really looked at this waterfall, or for the most part, even knew

it was there, were the locals who lived in a town a few miles away. But even they really

only saw it at a distance. Before 2005, everyone watched a waterfall, but no one went there.

You were fearful.

They would say kids, no, it's dangerous to go there.

You will die.

You get enchanted and he will stay there.

So no one, even the generations that followed, children, grandchildren, great-great-grandchildren,

no one would go to the waterfall.

And then in 2005, something happened that permanently changed the local's relationship with the waterfall,

and not necessarily in the ways you might think.

I'm Dilanthoris, and this is Alice Omskira. Today, I take you to a place that is very

near and dear to my heart. Gotta waterfall in Peru. That is after this. In 2005, a German researcher named Stefan Ziemendorf was out hiking in the Amazon region of Peru.

Stefan was in Peru working on a nearby wastewater project.

But on his day off, he decided to take a hike in the Utkabamba Valley in search of pre-Inken ruins.

And as he was hiking, came into a ravine, and Zeimendorf spied something off in the distance that wasn't on its map at all.

This towering, two-tiered waterfall.

So the following year, Stefan returned to the area,

and he brought along some measuring equipment with him.

He wanted to know just exactly how tall this waterfall was.

And to do that, he needed to go on an expedition

...