In 1177 Pope Alexander III sent his own doctor with a letter to Prester John, a Christian priest-king who never existed. Europe kept searching for him: in India, then Central Asia, then in Africa, where Ethiopia really was...

Namibia's desert is dotted with bare circles, and scientists still argue over what makes them. Sand termites, or the grass itself? Two research teams have published opposite answers. WHAT THIS SHORT SAYS Namibia's desert is dotted with bare circles, and...

MORE ON THE MAP: "Block or Mosaic?", our documentary on Africa's language map: Most of the world's languages never use click sounds. Xhosa and Zulu use them every day. Where did they come from? WHAT THIS SHORT SAYS - In...

Lake Bosomtwe (spelled Bosumtwi in science) in Ghana is almost perfectly round, and no river flows out of it. Why? An asteroid about a kilometre wide hit this spot just over a million years ago, and the proof...

MORE ON THE MAP: "Block or Mosaic?", our documentary on Africa's language map: In Ethiopia's Amharic, "name" is sim. In Morocco's Berber, isem. In Nigeria's Hausa, suna. Why do languages 5,000 km apart share a word? WHAT THIS SHORT...

Two thousand years ago, a kingdom in the Sahara grew wheat, figs and grapes, and Rome traded with it. They were the Garamantes, of Fezzan in south-west Libya. How did they farm in a desert, and why did...

In 2008, an Italian mineralogist exploring the Sahara on Google Earth spotted a sharp, round crater with pale rays around it, in the far south-west corner of Egypt. It was already in satellite images from 1972. An Egyptian...

Does Saharan dust really feed the Amazon? Follow it across the Atlantic: NASA satellites estimated about 28 million tonnes a year reach the Amazon basin, ground measurements later said 8 to 10 million. Real but modest, and African...

Ethiopia and Yemen both claim coffee. The oldest written proof of people drinking it comes from Yemen. But the plant itself was born in Ethiopia's forests, more than 600,000 years ago. Whose side are you on? Tell us...