Lake Titicaca, located on the border of Peru and Bolivia in the Andes Mountains, is widely recognized as the highest navigable lake in the world. It sits at an elevation of 3,812 meters (12,507 feet) above sea level. While there are smaller "tarn" lakes and glacial ponds located at even higher altitudes in the Himalayas or the Andes (such as Ojos del Salado at over 6,300 meters), Titicaca is the highest body of water that supports large-scale commercial shipping and regular passenger ferry services. It is an ancient, "endorheic" lake, meaning it has no significant outlet to the sea, and it is the largest lake in South America by both volume and surface area. In 2026, it remains a vital cultural and economic hub for the region, home to the indigenous Uros people who live on "floating islands" made of reeds. Its extreme altitude means the air is thin and the UV radiation is high, creating a unique ecosystem where specialized species, like the flightless Titicaca grebe, have evolved to thrive in the highland environment.