After the discovery of a bomb from World War II, around 20,000 people in Frankfurt am Main have to leave their homes at times. A restricted area with a radius of one kilometer was set up around the 500-kilogram explosive device, as the city, police and fire department announced on Monday.

“An uncontrolled detonation would mean massive damage to buildings and a great danger to human life.” Residents must evacuate this area by 9 a.m. on Wednesday.

The American bomb, weighing 500 kilograms, was discovered on Monday during construction work in the Bockenheim district. Only in extensive preliminary work can it be clarified how the bomb can be rendered harmless. “The explosive ordnance clearance service considers it possible that the bomb can only be defused by controlled detonation,” it said.