Using just one ladder, 20 firefighters scaled the height of Mount Everest in a world-record attempt in Cardiff.
Crews from South Wales Fire and Rescue Service climbed 8,848m (29,029ft) - the equivalent of the highest mountain in the world - on Saturday
The firefighters, dressed in full kit and wearing oxygen tanks, went up the ladder 1365 times in about four hours to finish the challenge.
Chief Fire Officer of SWFR Huw Jakeway said it was a unique challenge.
Starting at 11:00 BST the team, from Cardiff Central Fire Station scaled the ladder outside St David's Shopping Centre in the Welsh capital.
The firefighters took four hours 17 minutes and 22 seconds to finish the world-record attempt, cheered on by Fireman Sam.
Mr Jakeway told BBC Wales plenty of shoppers in the city stopped to support the firefighters in their charity challenge.
He said: "This has never been done before so the team are looking to set the world record."
After the challenge the crew tweeted: "We did it! We climbed the height of Everest in Full Kit/ BA's! Great fun and great support."