An unexploded bomb leftover from U.S. bombings of Germany in World War II was discovered and had to be disarmed over the weekend.

The bomb was first discovered in the Ostend area of Frankfurt in June while construction crews were working in the area. City officials, authorities, and emergency personnel promptly began evacuating the area on Saturday, starting with a nursing home close to the bomb. The evacuation area also included the European Central Bank, the central banking authority for members of the European Union using the Euro.

In total, 15,600 people had to be evacuated before disposal and emergency personnel could begin working to defuse the bomb.

Personnel began working on the bomb early Sunday morning after local Frankfurt police confirmed there was no one left in the area. The defusing lasted until mid-afternoon when local fire officials confirmed the bomb was safely diffused.

Frankfurt officials also explained that it chose to defuse it on Sunday to minimize impact on city life and operations.

Germany was subject to heavy bombing targeted at Adolf Hitler’s Nazi war machine in World War II, with industrial cities and important locations hit hard by U.S., British and Soviet bombers. While most bombs would detonate properly, there were plenty that didn’t and were left alone by local populaces or went unnoticed.