The Grand Harbour at Valletta is one of the principal natural harbours in the Mediterranean. The island of Malta was seized by Great Britain in 1800, and the Royal Navy adopted as a base a waterside arsenal that had previously belonged to the Knights of St John, and remained in use until 1979. Surviving features include an arcaded ropeworks, a hospital and a dry dock of the 1840s. Malta’s maritime museum is located in the bases bakery complex, built to the design of William Scamp in 1841-5, which originally housed 12 circular ovens for baking ships’ biscuits. Displays include many models and the steam engine of a dredger built in Scotland in 1951.