World War II ended in 1945 - 70 years ago - but on Wednesday, Cologne residents were forced to evacuate their homes and stay in school gymnasiums due to an aerial bomb.
A 440-pound bomb, believed to be dropped by the Americans as the war came to a close, was discovered along a riverbank during excavations for a heat pipeline, according to The New York Times. People living within a half-mile radius were forced to evacuate - homes, businesses, a nursing home, a youth hostel and a 45-story apartment building were all cleared out.
Schools were closed as 20,000 residents of Cologne took cover, according to The BBC. The device was discovered on May 22, but diffusing the bomb was scheduled for Wednesday.
Diffusing the bomb took less than a half an hour, but mass evacuations are common in Germany. Wednesday's evacuation was the largest since the end of the war seven decades ago, according to The New York Times, but six other explosives were found in the month of May causing several evacuations.
About 25 bombs annually are discovered and diffused in Cologne alone, according to the Wall Street Journal.
A 550-pound bomb caused 1,400 people in Erkrath, near Düsseldorf, to flee to safety while the bomb was being defused. In Hannover, more than 30,000 residents were evacuated after a bomb was discovered under what was once a school yard.
The official bomb squad attached to the Interior Ministry of North Rhine-Westphalia, the most populated state in Germany, defused 918 World War II-era bombs, as well as disposed of grenades and landmines.
The largest bomb disposal operation took place in December 2011, when two bombs dropped and undetonated during World War II were discovered in Koblenz lodged in the riverbed of the Rhine, according to the BBC.
"It is an issue in most major German cities, where anywhere from 5,000 to 10,000 unexploded bombs are believed to be lying under the ground," Sebastian Dosdall, head of GFKB-MV, a private company that specializes in clearing old munitions, told The New York Times. "It is a problem that will not be solved easily. It will be with us for quite a while yet."
