Tourists are tethered to an overhead guide rail, but encouraged to tiptoe to the very edge of the platform, balance over its rim or peer through the mesh at the pinhead people below. On a clear day the view is stunning.
"We want to get every adventurous thrill-seeker, and then we want to get everybody who wants to overcome fears and dig down real deep and do something that they never thought in their wildest dreams that they would ever want to do," said Jack Robinson, the tower's chief operating officer.
Overcoming his own fears, Robinson has done the walk three times as the tower ramped up a visitor program that formally starts on August 1. "I'm not an adventure seeker," he said. "But each time it's different, and each time it's exhilarating."
The tour starts with ground-level tests for explosives and alcohol, followed by safety talks and quadruple checks on safety equipment.
There's no jewelry, no cameras, no open-toed shoes and a waiver that includes the disconcerting line that "the activities involve risks and dangers that may cause serious personal injury and even death."
The outside portion of the tour lasts 20 to 30 all-too-short minutes, from the moment that glass doors open and the tourists venture, tentatively at first, onto the platform.
So far nobody has chickened out of the tour, which costs C$175 ($184) a go.
The 553-metre CN Tower, built in 1976, already boasted a glass floor on part of its viewing platform, prompting a how-much-do-you-dare game among its millions of visitors.
The brave run to the centre of the glass and jump up and down as if to test its strength, while the timid venture cautiously on to the first few feet. The nervous never make it onto the glass at all, preferring a horizontal view of the skyline from floor-to-ceiling picture windows.
The tower expects to recoup the money it spent installing the EdgeWalk adventure within four years.
Reuters