Taipei 101 was, for a few years, the tallest building on the planet. An architectural marvel, an imposing skyscraper erected in an area prone to earthquakes and typhoons. At 450 meters above the ground, tourists reach an observation deck where they can grab a bite to eat while enjoying views that, this past weekend, were very different. On the other side of the glass, they could see American climber Alex Honnold, 40. Curious onlookers took out their phones to film as Honnold waved to them from just inches away. Only a pane of glass separated them. Inside, comfort and curiosity. Outside, a man risking his life, climbing the building without ropes or safety equipment. One slip and it would be the end.

When they were little, many of them were afraid of heights. They couldn't go on fairground rides with their friends, and when a school trip involved climbing the tower of an iconic building, they couldn't look down. Now they scale the tallest buildings on the planet without ropes.