Visit to the magical Harry Potter Film Studios in Watford, London featuring the Great Hall, Diagon Alley, the Knight Bus, Privet Drive and one of the models of Hogwarts! Warner Bros. Studios, Leavesden is a 200-acre studio complex in southeastern England. Formerly known as Leavesden Film Studios and still colloquially known Leavesden Studios or simply Leavesden it is a major film and media complex owned by Warner Bros. The studios and backlot were all repurposed from the site's original use as a Rolls-Royce plc factory known as Leavesden Aerodrome, which was an important centre of aircraft production during World War II. It is situated in southwestern Hertfordshire approximately 18 miles (29 km) northwest of central London, in Watford. Warner Bros. Studios, Leavesden, is one of only a few places in the UK where large scale productions can be made. The studios contain approximately 500,000 sq ft (50,000 m2) of flexible space which includes stage space, one of the largest filtered and heated stage-based water tanks in Europe, production office space and support buildings, along with an extensive 80-acre (320,000 m2) backlot which offers a 180 degree uninterrupted horizon, favourable for exterior sets. Since acquiring the site Warner Bros. has opened a public attraction called The Warner Bros. Studio Tour - London, which sees over 5,000 visitors a day to the site whilst maintaining a secure studio space within the same complex. A succession of major feature films quickly made use of the site, including the first of the Star Wars prequels. By the year 2000, Heyday Productions had acquired the site on behalf of Warner Bros. for use in what would be the first in a series of films, Harry Potter and the Philosopher's Stone. Every one of the Harry Potter films was based out of Leavesden Studios over the following ten years. While other productions - mostly other Warner Bros. productions - made partial use of the studios, the site was mostly occupied by Harry Potter's permanently standing sets. During this time it was noted that there were some ways in which the site's facilities might be improved. None of the stages were adequately soundproofed and the WW2 era ceilings had a tendency to leak during rainy weather. One of the more noticeable exterior sets constructed on the Leavesden backlot (outdoors) was a row of ten houses (five per side) along a street, which was created for the Harry Potter series to represent Privet Drive. As of September 2012, this set is still visible on the Google Maps and Bing Maps aerial views of the area, along with the Hagrid's hut and Hogwarts bridge exteriors. On 21 March 2010, there was a fire on one of the Hogwarts sets during Harry Potter and the Deathly Hallows -- Part 2 at Leavesden Studios. Not much of the set was badly damaged. In 2010, Warner Bros. announced their intention to purchase the studio as a permanent European base, the first studio to do so since Metro-Goldwyn-Mayer in the 1940s. By November 2010, Warner Bros. completed its purchase of Leavesden Studios and announced plans to invest more than £100m into the site they had occupied for over ten years. The studios make Warner Bros. the only Hollywood film studio with a permanent base in the UK. Much of the redevelopment involved converting stages A through H into soundstages and equipping all the facilities with the latest fittings a production might require. The refurbished stages were retrofits of the original buildings and were very respectful to the site's storied and important history. As part of this redevelopment Warner Bros. also created two entirely new soundstages, J & K, to house a permanent public exhibition called The Warner Bros. Studio Tour - London, creating 300 new jobs in the local area. Currently the whole attraction is dedicated to the making of Harry Potter and is now home to many of the series' most iconic sets, props and costumes. It was opened to the public in early 2012.