Niger is a dino wonderland because of two chance geologic events. The first unfolded 180 million years ago, during the early Jurassic, when the great landmass Gondwana began to break apart, forming a massive depression in the center of what is now the West African nation, then a verdant region teeming with life. For millions of years, the depression took in sediment and the skeletons of dinosaurs and other creatures.

The second event happened 20 million years ago, when a volcanic hot spot raised what’s known as the Aïr Massif on the edge of this depression, tilting the strata upward and returning to the surface the now fossilized skeletons. Driving across these rock layers today, heading from Agadez into the open desert, is a journey through deep time.