A bomb dropped by the Britain during World War II has now exploded after being discovered in a canal in Poland. The Tallboy, also known as ‘earthquake bomb’ blew up 75 years behind schedule on Tuesday after a failed underwater operation to defuse it.

It weighed 12,000 pounds when it was dropped by the Royal Air Force during the final months of the war. It is the biggest bomb found in Poland and is assumed to have been used in a raid on the German ship Lützow.

The video shows the 5.4-tonne (12,000-pound) bomb exploding in a towering plume of water and steam under the Piast Canal, a key channel into the Baltic Sea for Germany’s warships during the Second World War.