The complex of underground rooms - over 32,000 sq feet - was built at the height of the Cold War, and then rebuilt in the 1980s at a staggering cost for the time of over £32 million.
Hack Green was declassified in 1993 and now serves as a fascinating museum that gives modern visitors a glimpse into a bygone world of secret cyphers, attack preparedness, and decontamination facilities.
Within the complex of rooms are a government communication centre, authentic equipment used to detect and monitor nuclear threats, a cypher room, radio room, and a labyrinth of corridors leading to dormitories and administrative facilities.
See a recreation of a Russian missile control room, a BBC studio, and numerous audio-visual presentations that give you an authentic taste of what life was like during the height of Cold War hysteria.
There is a special 'Soviet Spy Mouse Trail' for children - and, speaking from personal experience, our 10-year-old daughter loved it!
There is nothing quite like Hack Green; its an extraordinary place to visit, and sheds light on a strange and eerie world, when the threat of nuclear war was a constant and very real menace.
As of this writing, the bunker is open daily during spring, summer, and autumn, but please check the website for official opening times.