Toronto, Ontario - Spend 58 seconds soaring up in a glass-walled elevator at Toronto's CN Tower and you find the highest mailbox in the world, an elegant restaurant called 360 that and does a complete revolution every 72 minutes, and spectacular views from observation decks. On a clear day you may even be able to spot the spray from Niagara Falls. But, the really cool view is the one straight down when you step out on to a 6 cm (2.5 inches) thick glass floor, 113 stories above ground. Don’t worry, it’s strong enough to support at least a dozen hippos. In April 2008 the tower also added North America's first, and the world's highest, glass-floor-paneled elevator. The elevator has two glass panels, each 2 1/2 inches thick, which cover a total of six square feet of floor space. For more than 30 years the CN Tower was recognized as the World's Tallest Building, and it's been designated a Wonder of the Modern World.