Part of Glasgow was sealed off on Wednesday and about 400 people were evacuated from their homes after the device was deemed to be dangerous.
A digger working at the Meadowside Granary buildings on the River Clyde unearthed the 50kg (110lbs) bomb.
It was transported 20 miles to Duntilland Quarry in Salsburgh, north Lanarkshire, and detonated on Thursday morning during an operation which took about an hour.
Police said traffic restrictions put in place after the discovery had now been removed.
Emergency services created an exclusion zone covering three streets - Crawford Street, Sandy Road and Beith Street - and the Clydeside Expressway, which runs around the building.
The closure of the Expressway resulted in travel chaos for rush-hour motorists.
Experts from 33 EOD (Explosives Ordnance Disposal) at Stansted, Essex, arrived to make the bomb safe.
The Meadowside Granaries, made up of four buildings, have dominated part of the riverside skyline in the west end of Glasgow for almost a century.
Blitz theory
The buildings are now being demolished to make way for the Glasgow Harbour project, a major housing and retail development.
A Glasgow City Council spokesman said 50 people turned up to spend the night at Kelvin Hall in the west end but they were later moved to local hotels.
The spokesman said: "The rest of those evacuated from their homes appear to have found accommodation with friends and relatives."
On the decision to move the evacuees, the spokesman said: "It made more sense as it would be more comfortable for them to be in proper hotel accommodation.
"The Kelvin Hall would just have been a roof over their heads."
One theory is the bomb failed to detonate after being dropped during the blitz in WWII.