La Paz is built in a canyon created by the Choqueyapu River (now mostly built over), which runs northwest to southeast. The city sits in a bowl-like depression surrounded by the high mountains of the altiplano. As the city continues to grow, it climbs over the hills, the buildings clinging impossibly to the mountain side. The sight from the air as one flies into La Paz is incredible. “First, one sees the sprawling shantytowns of El Alto, slowly giving way to the sight of La Paz itself, clinging tenuously to the sides of what looks like a large gash in the earth”, writes WikiTravel.