The 500-kilogram unexploded bomb was unearthed during construction work on Wednesday in the densely populated Nordend area of the city, a location firefighters said made it a “particular challenge” to remove.
The Frankfurter Allgemeine newspaper reported the ordnance had been discovered right next to a children’s playground at a depth of about two metres (6.5 feet).
Its report said the controlled blast, which happened just after midnight, “sounded like thunder rumbling” and left a hole three metres deep and ten metres wide.
Firefighters said that they had covered the bomb with 40 truckloads of sand before detonating it, in order to minimise damage to the surrounding buildings.
Around 25,000 people had been asked to evacuate the area, including the occupants of a nearby community hospital’s neonatal ward.
❗ A WW2 bomb in Frankfurt‘s Nordend has to be defused as soon as possible❗
Please share! pic.twitter.com/yGkHCagOhF
— Frankfurt am Main (@Stadt_FFM) May 19, 2021
Among residents who took shelter at a skating rink was 29-year-old Tobias, carrying his pet cat in a cage.
He said he had heard the news over a police loudspeaker and been ordered to leave his home immediately, causing a “bit of stress”.
Barbara, 77, told AFP the news was “a bit of a shock, we don’t expect that”.
However, building works in Germany regularly unearth unexploded World War II ordnance, 76 years after the conflict’s end.
Seven bombs were defused in 2020 on land near Berlin where Tesla plans to build its first factory in Europe for electric cars.
Other bombs were also discovered last year in Frankfurt, Cologne, and Dortmund.
In Frankfurt, the discovery of a 1.4-tonne bomb in 2017 led to the removal of 65,000 people, the biggest such evacuation in Europe since 1945.