20,000 people evacuated after unexploded World War Two bombs discovered

It's the city's largest ever post-war evacuation.

It marks the largest ever post-war evacuation in the city.

Two 1,000kg and one 500kg American devices on Monday, with the size of the bombs meaning a 1,000m danger zone must be closed off.

Officials have been going door to door to ensure that all houses and businesses in the area are empty.

Among the buildings off-limits are nine schools, 58 hotels, a hospital, the main city hall, and the area close to Cologne's famous UNESCO-listed cathedral.

Shelters have been set up for those who were affected by the evacuation.

As reported by Sky News, City officials said the plan is to try to defuse the bombs, and if that isn't possible, another option would be to potentially try to detonate them safely.

According to reports, an estimated 1.5 million bombs were dropped on the German city during WW2, with 20% of those having not detonated.

Some of these 'duds' still remain beneath the city's streets, prompting several evacuations over the years.

Just last year, 31 bombs were found in the city, causing 17 evacuations which impacted over 36,000 people.