Toronto: 30 years ago today a Sikorsky Skycrane helicopter hoisted the final segment of the world’s tallest free-standing structure into place, officially topping off Toronto's (and arguably Canada’s) most famous landmark. The CN Tower will celebrate the pearl anniversary of this event today with ceremonies, festivities, and discounted tickets to the top ($30CAN for a party of 3).

The occasion is notable as it will likely be the last major anniversary the tower will celebrate while holding the title of “world’s tallest”. There are currently several other projects either approved or already under construction around the world aiming to take that title - not to mention the numerous other proposals and visions which constantly seem to sprout from the lofty minds of ambitious developers, architects and engineers (if not eventually from an actual construction site). Below is a list of some of the top contenders:

Project – City – Height(m) – Projected Completion Date
Burj Dubai – Dubai – 705m – 2008
Park Square Tower – Dubai – 666m – 2010
Guangzhou TV Tower – Guangzhou – 610m – 2009
Tokyo Sky Tree – Tokyo – 610m – 2010
Chicago Spire – Chicago – 610m – 2009
Jakarta Tower – Jakarta – 558m – 2009
CN Tower – Toronto – 553m – 1976