People swim in the Celeste river waterfall at Tenorio Volcano National Park in Upala March 18, 2008. The blue color of the lagoon, formed from chemical reactions of calcium carbonate and sulfur, is surrounded by amazing rainforest of 12,819 hectares of this park. The Celeste river carries its color for a distance of 36 km (22 miles).(Xinhua/Reuters Photo)
