Season 1 National Geographic , 2013 Watch now Season 2 National Geographic , 2015 Watch now Season 3 National Geographic , 2016 Watch now Season 4 National Geographic , 2017 Watch now Season 5 Russia's War National Geographic , 2018 Watch now Season 6 America's War National Geographic , 2019 Watch now Season 7 Battle Ready National Geographic , 2019 Watch now Season 8 National Geographic , 2019 - 2020
, 2013
