QUICK FACTSWhere is it? Emi Koussi, Chad [19.825520656, 18.551560720]What's in the photo? A patch of bright-white salt at the summit of the Sahara's tallest volcanoWho took the photo? An unnamed astronaut on board the International Space StationWhen was it taken? Dec. 29, 2024This intriguing astronaut photo shows a bright-white, salty surprise lurking at the summit of a giant volcano in the Sahara. The ancient, lava-covered peak also holds hidden, shadowy waterways, despite its extremely arid environment.Emi Koussi (also known as Emi Koussou) is a pyroclastic shield volcano in northern Chad. It's located within the Tibesti Massif, a volcanic mountain range that straddles the border between C...