Video tour: https://www.youtube.com/watch?v=_R5VfJzf5Bw

Naval Security Group Activity (NSGA) was an organization within the US Navy on Adak Island. It was tasked with intelligence gathering, cryptology, and denial of intelligence to Cold War and other adversaries. More than 700 military personnel were assigned to operations in these isolated facilities. Military activities lasted on this location from September 1943 until March 1997 when the entire Adak base was closed. But thawing arctic ice and geopolitical concerns has the US Navy considering a base reopening.