The weather for today's Geo Quiz is scorching hot, dusty and dry. That's because we're headed for one of the world's largest desert lakes.

It's located in Africa's Great Rift Valley. The lake is mostly in Kenya, but its northern tip extends into Ethiopia. This isn't exactly a swimming hole. There are lots of Nile crocodiles swimming about. Nasty snakes called carpet vipers slither along the lake's rocky shores.

Early humans traveled this remote desert landscape millions of years ago. And they left behind footprints that scientists have now discovered.

fossilized footprints: Lower hominin (human-like) footprint trail also shows more deeply embedded fossil animal prints towards far end of photo. Dated to 1.5 million years. (photo: http://news.rutgers.edu)

"This is a unique snapshot at one and a half million years ago. These footprints were gently in filled by water, and then sand grains in filled those prints and they were beautifully preserved."

Satellite view

John Harris is an anthropologist at Rutgers University, and he's been working with Kenya's National Museum to excavate the site. He says what makes these footprints unique... Is that they're the oldest ever found that look completely modern.