History of the world's tallest buildings
The buildings that were the tallest secular skyscrapers, which excludes religious buildings, were:
The list of tallest buildings is based on the default metric of the Council on Tall Buildings and Urban Habitat (CTBUH), that of measuring to the highest architectural element. Other criteria would generate a different list. Shanghai World Financial Center is not on the above list, but it surpassed Taipei 101 in 2008 to become the building with the highest occupied floor. Using the criteria of highest tip (including antennae), the World Trade Center in New York City was the world's tallest building from 1972 to 2000, until the Sears Tower in Chicago (which already had a higher occupied floor than the World Trade Center) had its antenna extended to give that building the world's tallest tip; a title it held until the 2010 completion of Burj Khalifa. Petronas Towers and Taipei 101 were never the world's tallest buildings by the highest–tip criteria.
Architecture of Toronto
The most prominent landmark in Toronto, and its best known symbol, is the CN Tower. It was the world's tallest free-standing structure for 31 years, from its completion in 1975 until Burj Khalifa in Dubai, United Arab Emirates surpassed it in 2007; it remains the tallest free-standing "tower" in the Western Hemisphere. The CN Tower is used as an observation tower, as well as a communications tower. Another landmark structure is Casa Loma. Constructed by E. J. Lennox during the early 1910s, it is a Gothic revival-style castle located on Walmer and Davenport roads. It was originally the residence of Sir Henry Pellatt, a Canadian financier and soldier. The city later took over the castle when Pellatt could no longer afford to keep it. The building presently operates as a museum.