Season 1 Smithsonian Channel , 2010 Watch now Season 2 Smithsonian Channel , 2011 Watch now Season 3 Smithsonian Channel , 2012 Watch now Season 4 Smithsonian Channel , 2013 Watch now Season 5 Smithsonian Channel , 2014 Watch now Season 6 Smithsonian Channel , 2015 Watch now Season 7 Smithsonian Channel , 2016 Watch now Season 8 Smithsonian Channel , 2017 - 2019 Watch now Season 9 Smithsonian Channel , 2021
, 2010
