The first cathedral was completed in 1092 at the now deserted Old Sarum, about 3 miles to the north of 'new Sarum' - modern Salisbury. Work on the present cathedral began in 1220 and was substantially complete by 1320. Salisbury Cathedral is a soaring Gothic masterpiece. It has the tallest church spire (404 feet - 123 metres), and the largest cloister and cathedral close in Britain, houses the world's oldest working clock, dating from 1386) and holds one of four surviving copies of the 1215 Magna Carta. Famously painted by John Constable, among its notable burials is ex-Prime Minister Edward Heath (1916-2005).