LARGE crowds gathered to see a Second World War bomb exploded in the mouth of the Helford River.
Bomb disposal experts were called in after the parachute mine was discovered just offshore by diver Mark Milburn, of Atlantic Scuba, Mabe.
He first found the device about half a mile from land in the mouth of the river two weeks ago, but was only able to get back down and take photos to send to experts last week.
The Royal Navy explosive ordnance device (EOD) diving team arrived on Friday and concluded it was an unexploded German parachute mine containing more than 700kg of high explosives.
Despite more than 60 years on the seabed, they said it was in "perfect condition".
The decision was made to carry out a controlled explosion.
They used underwater lift bags to move the device 200m farther from shore and place it back on the seabed.
However an emergency incident in Perranporth meant the explosion did not happen until Saturday (see second story).
Falmouth lifeboats were called, along with the coastguard cliff rescue team to ensure no boats or people were too close to the detonation site.
Mr Milburn found the 6ft by 3ft bomb while diving for scallops.
He said: "At first I thought it was a barrel, but on closer inspection I realised it was something else.
"It was exciting to see the bomb detonate, I did feel sorry for any marine life affected though.
"It was a huge device that was potentially dangerous, it had to be destroyed. The detonation made a quiet thud, but created a huge plume of water, which rose up more than 100 feet."
Mr Milburn is staging an underwater litter clean at Castle Beach on Sunday at noon. Any divers can take part.