Five visitors and one member of staff were injured
A number of people were injured when a lift in Tower Bridge, central London, fell 10ft.
The lift dropped in the north tower of the structure, the City of London Corporation said.
Four men and two women, including tourists from Spain, suffered leg injuries including at least one broken leg and a broken ankle.
The six were taken to hospital and about 10 people left the scene uninjured. An investigation has begun.
The City of London Corporation spokeswoman said: "The lift is believed to have fallen 10ft (3m) when it was on the way up from the (bridge level) ground floor."
The door to the lift opened automatically, she added.
The bridge houses an exhibition on the history of the London landmark. Five exhibition visitors and one member of staff were injured.
The spokeswoman added: "The lift takes a maximum of 40 people but it is not possible to say exactly how many people were in the lift."
Three ambulance crews and a hazardous area response team were sent to the scene at 1310 BST.
The six patients were all conscious when the crews arrived at the bridge, a London Ambulance service spokeswoman said.
They were taken to Royal London Hospital in Whitechapel, east London, and St Thomas Hospital, south-east London.
The City of London Corporation, which owns and manages the bridge, said it was co-operating with a Health and Safety Executive investigation into the incident.
The corporation's director of environmental services, Philip Everett, apologised for the incident.
"We are desperately sorry in causing this inconvenience," he said.
"We clearly very much regret it and we wish (the injured people) well."
Mr Everett said it was too early to speculate why the lift fell but added that the incident was "very concerning".
He said he was unaware of any previous problems with the lift, which carries about 1,000 people per day.
The Tower Bridge exhibition will remain shut until its other lift has been examined, Mr Everett said.
Four men and two women suffered leg injuries