Quelccaya Ice Cap, Peru

It’s an awe-inspiring sight: massive ice fields and blue-white glaciers span 27 square miles of the Cordillera Oriental mountain range. The Quelccaya Ice Cap, the largest body of ice in the tropics, feeds the streams and rivers of the valleys below. It has lost 20 percent of its surface area since 1978 and could disappear entirely by the end of the century.