History's Mysteries June 13, 2019 Underwater espionage: The surprising history of marine mammals and military service By Daniel Marzullo These units are conducting deep and shallow water mine countermeasure operations to clear shipping lanes for humanitarian relief. (Photo by Brien Aho/U.S. Navy/Getty Images). By Daniel Marzullo Share this: UP NEXT Bobby Dunbar mystery solved? DNA test puts 100-year-old mystery t... Next article: The spooky tale of Indiana’s ‘Witches’ Castle’ Related Articles: The spooky tale of Indiana’s ‘Witches’ Castle’ The legend of the Lost Dutchman The haunting history of La Pascualita Trending: Johnson was nearly impeached over Edwin Stanton