A 500kg (1,102lb) World War II bomb found in the River Mersey has been detonated in a controlled explosion.
The device was found by the Royal Navy during a routine survey at Twelve Quays dock in Birkenhead on Monday night.
Spokesman Neil Smith said it was "one of the most powerful and destructive" bombs dropped on the city during WWII.
Navy divers moved the 2.1m (7ft) German penetration bomb out to deeper waters in the Irish Sea to detonate it safely at about 2100 BST.
The explosion caused a plume of water about 9m (30ft) high into the air, about 13km (8 miles) west of Formby Point.
A 400 metre exclusion zone was set up around the bomb at the time of the blast.
The discovery of the device caused travel chaos on the Mersey as two passenger ferries were prevented from docking due to safety concerns.
The Mersey Viking, which had 64 passengers and 55 crew, and the Dublin Viking, which had 81 passengers and 46 crew, arrived in the dock on Tuesday morning but were unable to dock until the afternoon.
The Norfolk Line ferries had travelled to Liverpool from Dublin and Belfast.
The Wallasey tunnel and a Merseyrail line were closed for about 45 minutes when the operation began, but Merseytravel said disruption was kept to a minimum.
The bomb was a German air-drop explosive used in the blitz.
The Navy said it would probably have been dropped in an attempt to destroy the Liverpool docks.
Experts dragged the bomb to North Bar Light, an area identified by the coastguard where it could be detonated safely.
A diver then attached plastic explosives to the device in order to detonate it.
Royal Navy spokesman Neil Smith said the device may have lain undetected for so long because penetration bombs are designed to embed into a target before exploding.
He said: "This is only speculation, but if the bomb landed on the river bed it may have buried itself and only recently been uncovered by recent high tides, for example.
"It is a little more unexpected to find one so close to a city, and that obviously made it more challenging.
"Explosions under water are more powerful than those above water, so clearly we could take no chances with public safety in terms of reverberations affecting ships and tunnels, so some people were delayed.
"We apologise for any inconvenience but I think people understand that public safety is the main priority."