Egypt may not be the first place you’d look for whales, but once upon a time the Wadi Hitan desert was underwater and teeming with the sea giants.

Geologist Philip D. Gingerich and his team had excavated the first known nearly complete skeleton of a Basilosaurus isis. The first of the truly gigantic whales, Basilosaurus had the serpentine shape of a sea monster and short, sharp teeth for hunting sharks and other prey. Unlike today’s whales, it had no blowhole—the ancient behemoth had to raise its head above water to breathe. What’s more, Basilosaurus still had the feet it inherited from its land-dwelling ancestors.

Gilf Kebir is the most arid and desolate places on Earth, but thousands of years ago, the site had water and was inhabited by humans and animals. In the 1930s, Hungarian explorer László Almásy discovered prehistoric paintings in the Cave of the Swimmers, which gave a view into the life of a long forgotten civilisation. The video takes us inside the Foggini-Mestekawi cave, discovered in January 2003.