The central piece in a playground is a cool structure for kids to climb on. Yet, when adults build cool structures, at least in Europe, they don't make them climbable. I think there is some aesthetic rule that dictates people should not defile a beautiful piece.
The Chinese and Japanese have no such inhibitions. If they build something big worth looking at, they attach something so you can walk it, climb it, or otherwise ascend it and check it out from the inside and the top.
When I went up into the Pearl Oriental tower, there was a "sightseeing walk." The name was not that inspiring, but I was surprised to find out that this was a glass surface exposing you to all of the 250m of air underneath you. It was really cool.
The Sightseeing Walk in Oriental Pearl Tower
Compared to the World Financial Center, I thought the Pearl Oriental Tower was the better experience. You don't get quite the same exposure in the former. The World Financial Center had a cool space-theme going, though, with moody electronic music and interesting light effects.
In Tokyo, I went to view the International Forum, and again, was pleasantly surprised that they had built ramps so you could walk along the insides. It enabled me to view the structure from another perspective and get a better appreciation. The Kyoto Train station had the same feature, with stairs and 'skywalks' enabling you to walk up and down and across the appealing structures, viewing it and the surroundings from different angles.