The watch tower in Cairo, Indiana was commissioned in 1952 by the U.S. Air Force. During the Korean War it was manned 24 hours a day by 90 people, working in shifts, who would keep watch for Russian aircraft since there wasn't a national radar system at the time.
Towers - Misc, Abandoned, Military - Historic
The tower still stands, but due to its very poor condition you are not permitted to climb. There is also a monument with a man, woman, and child looking skyward.