The longest beaver dam in the world is 2,800 feet (853 meters) long. It's more than twice as long as the Hoover Dam in between Nevada and Arizona, which is 1,244 feet (379 meters) long. The dam was discovered from space using Google Earth and scientists estimate the beavers have been hard at work on the dam since the 1970s. The second longest beaver dam was discovered in 2007, also using Google Earth. It is 2,790 feet (850 meters) long and likely under construction for about 25 years.
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