Here, he gushes about the details of what makes a tall building and how it is measured. Judging can be to the top of the highest occupied floor, top of the roof, architectural top (including spires), and top of mast or antenna. Of course, the building must be freestanding and habitable too.
What counts? Taipei 101 wins everything but the “top of antenna” prize, which goes to the Sears Tower. The Petronas Towers are second tallest in most books, with the Empire State Building and Jin Mao Building rounding things out. What doesn’t count are the KVLY-TV tower (2063 ft tall), the Petronius offshore oil platform (2001 ft, including underwater structure), and the Canadian National Tower (1815 ft).
Ahh, just read Zach’s story to understand why or why not and what might be.
Related books: Building Big and Unbuilding by David Macaulay, Skyscrapers, and Devil in the White City (for a picture of how architecture and society were both changing during the birth of skyscrapers).