Djibouti, Lake Assal. An Afar camel caravan crossing the salt flats of Lake Assal, as shadows lengthen in the late afternoon. At 509 feet below sea level, Lake Assal is the lowest place in Africa. Each camel carries between four and ten thirty-pound sacks according to the size and maturity of the animal. The salt is sold across the border in Ethiopia. by John Warburton-Lee Photography
June 5, 2011 | a volcano in the Puyehue-Cordon Caulle chain of south-central Chile erupted after lying dormant for more than 50 years. The government evacuated several thousand residents as Puyehue threw ash more than 6 miles into the sky, pushing the plume toward neighboring Argentina. Authorities had already put the area around the volcano on alert after a flurry of earthquakes earlier on Saturday -- at one point, the tremors reached an average of 230 per hour.