LONDON (AP) — A World War II-era bomb whose discovery prompted one of the largest peacetime evacuations in British history has been detonated at sea, the Ministry of Defense said on Saturday.

The 500-kilogram (1,100-pound) explosive was discovered Tuesday in the backyard of a home in Plymouth, a port city on the southwestern coast of Britain. More than 10,000 residents were evacuated to ensure their safety as a military convoy transported the unexploded bomb through a densely populated residential area to a ferry slipway, from which it was taken out to sea.

“I think it is fair to say that the last few days will go down in history for Plymouth,” said Tudor Evans, the leader of Plymouth City Council.

Plymouth, home to major naval bases for centuries, was one of the most heavily bombed cities in Britain during the World War II. Fifty-nine separate air raids killed 1,174 civilians, according to local officials. The raids destroyed almost 3,800 homes, and heavily damaged another 18,000.