Martin Strel (pictured) claimed the record for longest swimming journey with a 3,273.38-mile trip down the entire length of the Amazon River. He began on February 1, 2007, in Atalaya, Peru, and finished 67 days later on April 8 in Belem, Brazil. On his shortest day, Strel swam less than six miles. On his longest day, he swam almost 80. The feat was made even more incredible by the number of dangers in the Amazon River, including crocodiles, debris, piranhas and electric eels.