The biggest World War II bomb detonated at the bottom of a Baltic Sea shipping canal in Poland during the defusing process.

Before the defusing process, more than 750 people were evacuated from their homes where the Tallboy bomb used by Britain’s Royal Air Force (RAF) was found. Dubbed the earthquake bomb, it was dropped by the RAF in 1945 in an attack on the German cruiser Lutzow.

Weighing almost 5,400kg, including 2,400kg of explosive, the bomb exploded while Polish navy demolition experts were trying to neutralize it underwater by burning out its explosives. However, the process turned into detonation.

The shock was reportedly felt in parts of the city. A video on social media shows the blast throwing up a large column of water into the air.

The spokesman of the 8th Coastal Defense Flotilla Second-Lieutenant Grzegorz Lewandowski said no one was injured because all the divers were at a safe distance from the blast.