City high-fliers have taken part in one of the most ambitious and terrifying charity fundraising events in the finance centre's history today (7 September). The City Three Peaks Challenge echoes the original event that dares climbers to ascend Mount Snowdon, Scafell Pike and Ben Nevis replacing them with landmark skyscrapers; The Gherkin (30 St Mary Axe), The Cheesegrater (The Leadenhall Building) and The Walkie-Talkie (20 Fenchurch Street).

Risking life and limb for charities The Outward Bound Trust, the Royal Navy and the Royal Marines Charity were representatives from City firms including AkzoNobel, hedge fund managers CQS and Talbot Underwriting. Each participant committed to raise £100,000, with the aim of generating £4m for good causes.

The event, which takes the participants into the record books as it is the first time abseiling down all three buildings has been attempted, follows the Descent of the Shard event in 2012, when the Duke of York, the chairman of trustees for The Outward Bound Trust was joined by volunteers to abseil down London's tallest skyscraper raising £2.8m for charity.

Nick Barrett, chief executive of The Outward Bound Trust said: "Following the unprecedented success of the Descent of the Shard three years ago, we wanted to do something even bigger and better, and are absolutely thrilled to have secured support from 30 St Mary Axe, The Leadenhall Building and 20 Fenchurch Street to help bring our vision to life."

"The funds raised will be instrumental in the opening of a brand new centre, which will reach 10,000 more individuals, not to mention the support it will provide serving personnel, veterans and families through the work of The Royal Navy and Royal Marines Charity."

Funds raised from the event will help support 9-19-year-olds access challenging and adventurous Outward Bound experiences. Barrett added: "It's not often we get the opportunity to raise money on such a large scale with so much support and we're extremely grateful to the individuals who have committed to our project."