RAF Harpur Hill was a Royal Air Force base, situated at Harpur Hill near Buxton, Derbyshire in England. The site was operational from 1938 to 1960 and was mainly used as an underground munitions storage facility it became the largest ammunitions dump in the country across the 500 acres (200 ha) site From December 1939 to December 1960, the RAF Maintenance Unit 28 was based at Harpur Hill. The RAF used Harpur Hill as a underground munitions store. In 1938 the Air Ministry bought a local quarry from ICI. 11 tunnels were built (concrete galleries covered by waste quarry stones) and dug into the hillside from 1938 to 1940 by McAlpine (at a cost of £6,500,000) to house munitions (ammunition and weapons) and ordnance (bombs and explosives) during World War II. The original wartime RAF camp at Harpur Hill was a top secret facility and was heavily defended. The camp's housing for staff was built nearby on roads named after past RAF war heroes (such as Nettleton, Tedder and Trenchard). A new site was constructed lower down the hill after the war. Bombs continued to be stored underground during the 1950s. The RAF base was closed in 1961.Many of the defensive bunkers can still be seen in the surrounding hillside .