Chacaltaya, Bolivia

The snow-covered peaks of Chacaltaya Mountain tower over the Bolivian capital, La Paz, rising 17,800 feet above sea level. The Chacaltaya glacier is more than 18,000 years old, and its meltwater is an important resource for the inhabitants of La Paz. In the last 20 years, however, the glacier has shrunk 80 percent in volume. With temperatures expected to continue to rise, the glacier could eventually disappear completely.