The Stanley R. Mickelsen Safeguard Complex was the United States’ first operational ABM (anti-ballistic missile) defense system.
This outwordly base, a construction whose geometry resembles the ancient Mayan ruins found at Chichén Itzá (photo, below, taken by photographer Henry Sweet during a 19th-century archaeological journey led by Alfred P. Maudslay. Source: G.Manaugh), was briefly used to track Russian incoming warheads and shoot them down with Spartan (long ranged – atmospheric) or Sprint (“last ditch” interception) -class anti-ballistic missiles.
Built in 1970 at a cost of six billion dollars in Nekoma, North Dakota, (following the introduction of the Safeguard plans in the late 1960’s), the site included, apart of the giant pyramid-frustum shaped radar system, dozens of launching silos for surface-to-air missiles tipped with thermonuclear warheads. The excessive expenses, as well as concerns over the danger and the effectiveness of the defense (-the Russian missiles would be shot down over Canada-), were the main factors that brought the base to be shut down after being operational for only three days. The massive tunnels were flooded and the shell still stands today in the middle of nowhere, lasting as “a monument to man’s fear and ignorance.” (as someone wrote).
The Library of Congress site just released a lot of original files, documenting the complex and its construction with original photographs, plans and execution drawings. If you are interested, there are a lot of further links to dedicated sites and articles at the end of this post.
srmsc.org, a site entirely dedicated to the Stanley R. Mickelsen Safeguard Complex, with tons of original documents and reports, among which: a system overview, Maps, the impact of this base’s construction and subsequent closure on the little town of Nekoma.
A Google Maps aerial view of the site
Video: The Safeguard ABM System
Video: AT&T Archives: A 20-year History of Antiballistic Missile Systems (1976)