The Ahaggar Mountains, also known as the Hoggar, are a highland region in central Sahara, or southern Algeria, along the Tropic of Cancer. They are located about 1,500 km (900 mi) south of the capital, Algiers and just west of Tamanghasset. The region is largely rocky desert with an average altitude of more than 900 metres (2,953 feet) above sea level. The highest peak is at 3,003 meters (Mount Tahat). Assekrem is a famous and often visited point where le Père de Foucauld lived in the summer of 1905. The main city nearby the Ahaggar is Tamanghasset, built in a desert valley or wadi.