Children were among 19 people rescued from a fairground ride which became stuck 20 metres above the ground.
Firefighters spent more than three hours retrieving 13 adults and six children from the attraction on the South Bank in central London on Sunday night.
There were no reported injuries and it is not known what caused the ride - which has capsules that swing around a central pillar - to stop working.
London Fire Brigade (LFB) used two cherry-picker-style aerial platforms to bring people down from their seats in an operation that lasted several hours.
Crews also worked with an onsite engineer to manually release the ride's friction brake so that it could be turned around and aligned with the aerial ladder.
LFB station manager Clive Robinson said people on board had waited patiently to be rescued.
"It was slow work as we need to access each cage on the ride individually and ensure they were secure before we move them from the ride onto our platform and bring them back down to the ground.
"There were no injuries and everyone was patiently waiting for us to get around to them.
"While everyone was very relieved to be back on the ground, everyone was very calm."
A spokeswoman for the Health and Safety Executive said: "We are aware of the incident and we are making inquiries."
Metropolitan Police officers placed a cordon around the ride to ensure the fire brigade could carry out the work away from crowds.
The cause of the incident remains unknown.
Chris Cotter and Pegah Souri arrived at the South Bank at around 8.30pm when there were still three sets of people stuck mid-way up the broken ride.
Mr Cotter, 23, from Oxford, said: "We just came to get a drink and it was only when we got to the top floor up there that we realised there was something wrong with the ride.
"There were like three fire engines around it, just helping people off on the cranes.
Asked about whether people seemed worried he said: "It's kind of difficult because everyone here is like having a good time, having drinks - you're probably not quite aware of the panic that's happening like 50 ft up in the air.
"There was a fireman at the entrance to the ride explaining what was happening, but it all seemed really under control.
"We were talking about theme park rides. It's like the one thing you don't want to happen on a theme park ride is get stuck on the top.
"But they seemed to do all right and they seemed to get more than their money's worth on the ride."
The hanging capsules were still swinging in the wind half-way up the ride as last orders were called in the surrounding drinks area, just after 10.30pm.