Lying at nearly 13,000 feet on the border between Peru and Bolivia, Lake Titicaca is the second largest in South America, with an area of 3,232 square miles. Its many islands include the Isla del Sol, which the Incas believed to be the birthplace of the Sun God. Today, the thriving city of Puno dominates the northwestern shoreline, while elsewhere, the native people exist much as they have for centuries, harvesting reeds to build boats and artificial floating islands on which many of them live. Thanks to the altitude, the surface of Lake Titicaca is an astonishing luminous blue and reflects the peaks of Bolivia’s majestic Cordillera Real, notably 21,086-foot Mount Ancohuma and 20,867-foot Mount Illampu.