The Sahara Was Once Underwater

Long before it became the world's largest hot desert, much of the Sahara was a vibrant marine world at the bottom of the Tethys Sea. For millions of years, this ancient ocean separated the supercontinents of Laurasia and Gondwana. The dramatic transformation from sea to sand was driven by plate tectonics; as the African plate drifted northward, it slowly closed the Tethys, uplifting the seabed and eventually creating new land where a deep ocean once existed.

The proof of this aquatic past is etched into the desert landscape. In Egypt's Wadi Al-Hitan, or "Valley of the Whales," the complete skeletons of early, serpentine whales like Basilosaurus lie exposed by the wind, alongside the fossilized remains of giant sea turtles, crocodiles, and massive shark teeth. Beyond these spectacular finds, the very rock itself tells the story. Vast deposits of limestone, formed from the compressed shells and skeletons of countless tiny marine organisms over eons, create much of the bedrock of the region