The Skyline Challenge on September 28 will be in aid of the Construction Youth Trust, which helps young people from challenging backgrounds to prepare and find work in the construction industry.
Up to 200 people, in teams of 4, will run up 39 floors of the Heron Tower using its panoramic staircase.
Beneficiaries of the Construction Youth Trust will also be competing, marshalling, and presenting some of their recent works on the top floor, according to RBS, whose graduate programme is helping to organise the event.
Registration starts at 9.45am.
You can find all the details here: