Simon's Town became the base of the Royal Navy's South Atlantic squadron in the 1800s. The harbour was expanded and a dry dock built in 1910 which was the largest of its kind in the southern hemisphere. Through the 20th century, the port's strategic position at the hinge point of the sea route around Africa was of increasing importance. With the Suez Canal closed during World War 1, and enemy attacks menacing Allied shipping in the Mediterranean in World War 2, the Cape sea route became an essential artery. Some 170 warships and 60 merchant vessels were repaired in the dockyard during the 1939-1945 war, and the port provided valuable respite - and some recreation in its taverns - for the men passing through. In the 1950s, the naval base was transferred to the South African Navy under the Simon's Town Agreement, and today it hosts South Africa's fleet of modern corvettes and submarines.