Cracroft Caverns, also known as the Cashmere Caverns, is a set of large wartime chambers in the hill of the Cashmere suburb of Christchurch. Work began in 1942 in secret, to build an operational headquarters in case of attack, on the Cracroft Wilson estate. The largest cavern is about 7 metres high, 10 metres wide and 30 metres long, and is lined with prestressed concrete. Work stopped in 1944, and the entrances were sealed after the war. The caverns were rediscovered in 1987, and later housed ring laser experiments by the University of Canterbury's physics department. A small public park lies behind Princess Margaret Hospital.
Parts of the caverns have been open to the public in the past. Damage from the 2010 and 2011 Canterbury earthquakes means there is currently no public access, the website says. One customer found it open on one day, with no one inside.