Salisbury Cathedral, formally known as the Cathedral Church of the Blessed Virgin Mary, is an Anglican cathedral in Salisbury, England, and one of the leading examples of Early English architecture. The main body of the cathedral was completed in only 38 years, beginning in 1220. The cathedral has the tallest church spire in the United Kingdom reaching 404 feet. Visitors can take the "Tower Tour" where the interior of the hollow spire, with its ancient wood scaffolding, can be viewed. The cathedral also has the largest cloister and the largest cathedral close in Britain spanning some 80 acres. It contains the world's oldest working clock and has the best surviving of the four original copies of Magna Carta.