The German city of Cologne has finished evacuating 20,500 people, its largest evacuation order since World War II, after officials defused three massive, unexploded bombs.

Cologne was the first German city to experience a '1,000 bomber raid' by the Royal Air Force during World War Two. Some 1,400 tons of bombs were dropped in a single night on 30 May, 1942.

Cologne was the first German city to experience a '1,000 bomber raid' by the Royal Air Force during World War Two. Some 1,400 tons of bombs were dropped in a single night on 30 May, 1942.