Canada's eager beavers build world's largest dam

This undated satellite image made available by Google Maps shows a beaver dam, more than eight football fields long, situated in northern Alberta's Wood Buffalo National Park which straddles the Alberta-Northwest Territories border. Ecologist Jean Thie said Friday, May 7, 2010, that he found the dam using Google Earth and NASA technology in 2007 while researching the rate of melting permafrost in the country's wetlands. (AP Photo/Google Maps)