Guarding the approaches to both Grand and Marsamxett Harbours is Fort St Elmo. It was the scene of a heroic defence during the Great Siege of 1565.
When the Knights arrived in Malta, Mount Sceberras, on which Valletta was later to stand, was a rocky promontory with a small fort built in 1488 during Aragonese rule of the Islands. The Knights set about reinforcing the fort's defences to the extent that this once small fort managed to repel a month of attack from the Ottomans at the outset of the Great Siege. It was eventually captured with the loss of 1500 Knights and local defenders. But testimony to the Fort's strength is the fact that the attackers lost four times that number of men in taking the St Elmo. When the siege was over, the victorious Knights rebuilt Fort St Elmo and strengthened further its defences. The Fort has seen continuous use over the centuries, right through to World War II and the present day. In 1940, at the start of the War, Italian airmen led the first aerial attack on Malta with Fort St Elmo as the main target.