Volunteers clearing up a stretch of canal in east London unearthed an unexploded grenade from World War Two.
The live grenade was found at about 15:00 GMT along a stretch of Regent's Canal near Salmon Lock in Mile End.
Scotland Yard said it was alerted by the Canal and River Trust, which organised the event, and it took the grenade away to dispose of it.
Debbie Vidler, from the trust, said: "We often find weird and wonderful things in the bottom of canals."
She added: "Today we discovered numerous shopping trolleys, bicycles, mobile phones... but we were not expecting to find a 70-year-old unexploded bomb."
