Season 1 National Geographic , 2009 Watch now Season 2 National Geographic , 2011 Watch now Season 3 National Geographic , 2011 - 2012 Watch now Season 4 National Geographic , 2012 - 2013 Watch now Season 5 National Geographic , 2013 Watch now Season 6 National Geographic , 2014 Season 7 National Geographic , 2015 Season 8 A&E , 2026 Watch now
, 2009
