Construction workers discovered the 1,000-kilogramme American bomb on Monday afternoon at a work site in the city centre, police said on on Tuesday.
Before the Lower Saxony ordnance clean up team attempted to defuse the bomb, emergency workers evacuated a 3-kilometre area using radio announcements, patrol cars and even a helicopter to get residents' attention. Police also set up areas for people to wait during the clean up.
Bomb experts defused the bomb at around 1 am on Tuesday morning.
More than 60 years after the end of World War II, weapons recovery remains an important task for police and private companies throughout Germany. Allied forces dropped more than 2.7 million tonnes of explosives across Germany during the war. Some of the ordnance did not explode and has become increasingly dangerous with time and corrosion.
Another major ordnance find cropped up on the Baltic Sea coast in September 2008 when municipal workers spotted a four-metre long (12-foot) piece of a World War II era torpedo near the Timmendorf beach.
Entire neighbourhoods are frequently evacuated for bomb removal, and most are defused without incident. Construction and road workers are trained to call emergency services the moment they suspect they've found unexploded ordnance, but accidents still occasionally happen.
People are periodically killed when they stumble upon old war explosives around the country. In 1994, three construction workers were killed and eight bystanders injured when an unexpected bomb detonated, tearing through nearby buildings and cars in Berlin. In 2006, a road worker was killed near Frankfurt when his excavator hit a bomb.