More than 50,000 residents from the German city of Augsburg were evacuated from their homes so that a huge World War Two bomb could be defused.
It was the country’s biggest evacuation for an unexploded bomb since the end of the war.
The 1.8-tonne British explosive is thought to have come from a 1944 air raid, which destroyed the old town.
German police later announced that the bomb had been made safe.
Officials chose Christmas Day for the evacuation because it was less difficult than on a normal working day.
The bomb was uncovered during construction work on Tuesday.
Augsburg mayor Kurt Gribi, speaking in a video posted on the city’s Twitter account as the evacuation began, called for “each person to verify that their relatives, parents and friends have found places to stay outside the [security] zone … Look out for one another.”
The authorities were confident that most people affected could stay with friends or family, but a number of schools and sports halls were opened as shelters for those in need.
Most Germans celebrating Christmas open their presents and have their main festive meal on 24 December, rather than Christmas Day.
•May 2015: 20,000 people in Cologne forced to leave their homes after a one-tonne bomb was discovered
•January 2012: A construction worker was killed when his digger hit an unexploded bomb in Euskirchen.
•December 2011: 45,000 people were evacuated from Koblenz after two bombs were found in the riverbed of the Rhine. It took three hours to make them both safe.
•June 2010: Three members of a bomb disposal squad were killed in Goettingen during an operation to defuse a bomb found on a building site.