On Wednesday, over 20,000 people in Germany had to leave their homes after the discovery of three aerial bombs from World War II. The bomb squad anticipated that safely removing the bombs would be a lengthy process.

These bombs were uncovered during preliminary work in Cologne, Germany, on Monday. This led to what officials described as Cologne’s largest evacuation since World War II, as reported by the Associated Press.

City authorities stated in a news release that the bombs consisted of two American 2,000-pound bombs and one American 1,000-pound bomb, all equipped with impact fuses, which required defusing.

This operation prompted the evacuation of 20,500 residents from their homes in order to prepare for the operation.

More than 20,000 residents needed to evacuate an area in Cologne, Germany, after three World War II bombs were found. (Thomas Banneyer/dpa via AP)

“The three World War II bombs in Deutz have been defused. At 7:19 p.m., the three unexploded bombs that had paralyzed large parts of the city were defused,” the post read. “The closed streets and bridges are now gradually being reopened, and residents can return to their homes or are being brought back by ambulance or shuttle buses.”

According to the National WWII Museum in New Orleans, Cologne was a frequent target for Allied air raids, with the first of 262 happening on a May 17, 1940, Royal Air Force bombing mission.

The defusing of the three World War II bombs took nearly 12 hours. (Thomas Banneyer/dpa via AP)

During that time, 770,000 residents evacuated the city, leaving about 20,000 behind.

The final bombardment was on March 2, 1945. American tanks entered the city a few days later.

Nick Butler is a reporter for Fox News Digital. Do you have any tips? Reach out to Nick.Butler@Fox.com.