Lake Titikaka Lake Titikaka, at 12,530 feet, is the highest navigable lake and the center of a region where thousands of subsistence farmers make a living fishing in its icy waters, growing potatoes in the rocky land at is edge or herding llama and alpaca at altitudes that leave travelers gasping for air. It is also where traces of the Spanish conquistadors' aggressive campaign to erase Inca and Pre-Inca cultures and, in recent times, the lure of modernization. The deep blue Lake Titikaka is so large that it has waves. This, the most sacred body of water in the Inca Empire and now the natural separation between Peru and Bolivia, has a surface area exceeding 3,100 square miles, not counting its more than 30 islands. The best-known of the islands dotting Titikaka's surface are the Uros, floating islands of reed named after the Indians who inhabited them. The Uros' poverty has prompted more and more of them to move to Puno. That same poverty has caused those who remain to take a hard-sell approach to tourists and, besides pressing visitors to buy their handicrafts, they frequently demand "tips" for having their photographs taken.