Website developed by the U.S. Geologhical Survey, an American Institute devoted to provide scientific information on all topics related to Earth and environmental issues. In this educatonial webpage, they offer information on many aspects of water, along with pictures, data, maps, and an interactive center where users can give opinions and test their water knowledge. It is possible to choose a topic from the available menu, get a description of main water topics, and view the site map. This Web site is also available in Spanish, and is fully advisable for students, teachers and educational professionals