Bletchley Park was the headquarters of British intelligence during World War II. Once a baronial estate, the mansion and 59 acres of surrounding grounds became a beehive of intelligence activities designed to defeat Nazi Germany.

Bletchley Park is perhaps best known for the work done by mathematicians Alan Turing and Hugh Alexander, among others, to break the German codes and other ciphers. The work of Bletchley Park gave the U.S. allies a crucial advantage over Germany and helped win World War II.

Turing’s story is told in the movie “The Imitation Game.”

After the war, the British codebreaking office was renamed the General Communications Headquarters (GCHQ). It is the equivalent of America’s National Security Agency.

Now rare footage has surfaced of showing the codebreakers who worked for British intelligence service, the MI6, at the time.

“This unprecedented discovery provides us with a rare glimpse into the world of people occupied in some of the most secret work of World War II.”