Firefighters from around the globe will climb New Zealand's tallest building on Saturday, wearing 25kg of kit for a good cause.
One thousand people will run up the Sky Tower's stairs to raise money for Leukaemia and Blood Cancer NZ.
CEO Peter Fergusson says it's amazing to see so many people up for the task.
"Climbing the tower is no easy feat - 1103 stairs, 51 storeys - the tallest building in the southern hemisphere. And the guys are fully-kitted up - they're in full firefighters' uniform."
Photographs of survivors and those who have passed will decorate the walls and uniforms of competitors.
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Ten percent of the New Zealand firefighting force will participate.
"It makes a huge amount of difference to the people around New Zealand," says Fergusson. "Our staff on the ground contact around about 19,000 patients and families a year. It helps us getting around."