17 December 1969 December 16, 2020 Author: Staff Project Blue Book: The United States Air Force closes its study of UFOs. Famous Words of Inspiration..."Extraordinary claims require extraordinary proof." Carl Sagan — Click here for more from Carl Sagan Related posts: 20 May 1969 4 December 1969 21 December 1969 10 February 1996 30 January 1969 17 December 1892 20 January 1969 17 December 1892 1 September 1969 19 November 1969 Categories: History Tags: 17 December, 1969