Not far from the capital lies the world's highest navigable lake, Lake Titicaca. Clear blues of the sky hit the dark blues of the water while the white horizons of snow and mountains merge hazily with the dusty dry shores of this legendry lake. Evidence of its religious importance to both the Inca and Aymara Indians abound and include a sacred fountain, the Inca steps and religious sites on both the Sun and Moon Islands. Between La Paz and Lake Titicaca are the remarkable ruins of Tiahuanaco. Believed to be the cradle of the American civilisation dating back to 1,600 B.C. this ceremonial complex was at one time, the 'largest city in the world'.