Largest conventional explosion

The largest single conventional explosive detonation was for the demolition of the German fortifications at Helgoland on 18 April 1947. A charge of 4,061 tonnes (8,952,961 lb) was detonated by Commissioned Gunner E.C. Jellis of the British Royal Navy demolition team ,headed by Lt. F.T. Woosnam aboard HMS Lasso lying 14.5 km. (9 miles) out to sea. Helgoland is a German island in the North Sea, a rock of red sandstone with an area of 160 ha (395 acres). During both World Wars it served as a major naval base and was known as "Germany's Gibraltar". In particular it had significance as a submarine pen for U-boats preying on Allied shipping. Part of Helgoland's fortifications were demolished after World War One, in accordance with the Treaty of Versailles. However the Nazi government rebuilt them. Following the defeat of Hitler, the British forces occupied Helgoland and expelled the population so it could use explosive charges to completely destory all military facilities on the island. After this was completed in 1947 Helgoland was used as a bombing range by the Royal Air Force until the United Kingdom returned it to Germany in 1952.