An Afar camel caravan crosses the salt flats of Lake Assal, Djibout. At 509 feet below sea level, Lake Assal is the lowest place in Africa. Extremely high midday temperatures which force the Afar to arrive in the late afternoon and immediately set about collecting salt from deposits that are at least 109 feet thick. Each camel carries between four and ten thirty pound sacks according to its size and maturity.