Italian police evacuated 55,000 people from the centre of Milan while an army bomb disposal team defused an unexploded World War II bomb.
The bomb was in perfect condition
The weapon was found during the excavation of a building site near Milan's central railway station.
The unexploded 1,000-pound bomb was dropped by the allies during the bombing of Milan in the war.
Residents have been able to return home after police gave the all clear and took the bomb away.
Experts said it could have exploded when a mechanical digger brought it to light.
Shortly after dawn police began evacuating people living within a radius of one kilometre from the building site.
Traffic at one of Europe's busiest railway terminals nearby came to a halt during the bomb disposal operation and all trains were diverted to other parts of the city.
Elderly people and children were taken to local schools and given meals and hot drinks while an army bomb disposal team defused the bomb.
Experts said it was in a perfect state of conservation.
The bomb was successfully defused after about two hours of work.
It will be transported to an underground quarry on the city outskirts where it will be blown up in a controlled explosion.