headquarters until 1818, when it became the summer headquarters of the station. Defences were built around the approach towards the basin's entrance, with the construction of the York Redoubt at Ferguson's Cove, as well as fortifications on Georges Island, and McNabs Island. These defences were a part of the Halifax Defence Complex. In 1907, the Royal Naval Dockyards was transferred to the Government of Canada, and continues to operate as CFB Halifax. In December 1917 the basin was the site of the world's worst non-nuclear explosion - generally known as the Halifax explosion. The basin played a key role during the First and Second World Wars when the German navy used submarines to disrupt Allied shipping. Given the size of the Port of Halifax, and its vicinity to Europe in contrast to other North American ports, the basin was used as an assembly point for Atlantic-convoys bound for Europe. With defences built just outside of the only access point into the basin (a strait called The Narrows), it provided the Royal Navy and Royal Canadian Navy a safe place to assemble its convoys consisting of hundreds of merchant ships in relative security, while torpedo nets kept German submarines at bay. In 1994, the defences that protected Bedford Basin were designated a National Historic Site of Canada, commemorating the assembly of convoys in Bedford Basin during the Second World Wars. A plaque was erected at Admiral Harry DeWolf Park on the Bedford waterfront. The park derives its name from Admiral H.G. DeWolf, of the Royal Canadian Navy. In 2010, on the 100th anniversary of the Royal Canadian Navy, a plaque was unveiled at Bedford Lake, Griesbach, Edmonton, Alberta, in recognition of the role played by Bedford Basin, Nova Scotia, in World War I and World War II. "Bedford Basin is a large enclosed anchorage, forming the northwestern end of Halifax Harbour in Nova Scotia on Canada's Atlantic coast. The basin is quite deep and the good holding ground on the basin floor makes it an ideal anchorage and a protected location for ships. The Basin came to international significance during both the First and Second World Wars when the German navy began to use submarines as an offensive weapon against Allied shipping Canada's prominent role in the First World War led to Halifax being chosen as the primary logistic port for resupplying Western Europe. The protected waters of Bedford Basin allowed