The World's Tallest Freestanding Structure

It is found in downtown Toronto, Ontario. Beyond its height, it is known for its Glass Floor, Revolving Restaraunt, Huge Arcade, and the neighboring SkyDome.

Serving as the Toronto skyline's most distinctive feature, the CN Tower was "The World's Tallest Free Standing Structure" until September 13, 2007 when it was eclipsed by the Burj Dubai. ('Free standing' meaning not supported by external cables, as some taller TV antennae are.) It serves as both a telecommunications hub and a tourist attraction (about two million people visit every year). The Tower is one of the ASCE's Seven Wonders of the Modern World.


The CN Tower was built by Canadian National (CN) who wanted to build a tower taller than any other in the world. The tower's construction involved over 1,537 workers and in excess of 4,800 man-hours each. Construction began on February 6, 1973 and in only 4 months a thick, Y-shaped, concrete and steel foundation had been laid. The foundation is 6.71 m (22 ft) deep. According to the IEEE website, "the foundation contains 7,046 cubic metres (9,200 cubic yards) of concrete, 453.5 metric tonnes (500 tons) of reinforcing steel and 36.28 metric tonnes (40 tons) of thick, tensioning cables."

Final, total height: 553.33m (1,815 ft., 5 inches)


The Tower's microwave receivers are located 338 m (1,109 ft) above the ground in the radome, as well as VHF, UHF and television equipment. Incoming signals are monitored and fed to the Tower's antenna for retransmitting. The radome is designed to protect the reception and transmission equipment from the elements without disabling its ability to receive transmissions.

Parts you can visit

At 1,122 ft (342 m.) is the first level, featuring the "Glass Floor" and the Outdoor Observation Deck. (I lay on the Glass Floor today after doing the United Way Stair Climb. Way cool!)

One level up, at 1,136 ft. (346 m.) is affordable food at the Horizons Cafe and the Indoor Observation Deck.

At 1,150 ft. (351 m.) is the revolving restuarant, 360. Don't eat here unless someone else is paying. The food is good, but the prices are (sorry) sky-high. The floor in the 360 Restaurant rotates through an entire revolution once every 72 minutes, which is just right for a relaxing meal on someone else's tab.

Finally, for an extra fee, you can ride up to the Sky Pod, at 1,465 ft. (447 m.).

If you'd rather skip the admission charge

For charity events, you can climb the 1,776 steps of the interior stairwell. This takes about half an hour -- 24 minutes for myself, at age 35 and in decent if unremarkable shape. They let you ride the elevator back down.


The CN Tower is located beside the SkyDome, just south of Front Street in downtown Toronto. The CN Tower is easily accessible by surface routes or the covered SkyWalk from Toronto's Union Station

Other Tall Things

The Las Vegas Stratosphere was an attempt to surpass the CN Tower. It failed for reasons unknown to yours truly, and now hosts the world's tallest amusement ride (the Space Shot) or some such thing. Las Vegans, please elaborate under Las Vegas Stratosphere or similar.

The Petronas Towers in Kuala Lumpur, Malaysia, is the World's Tallest Building, that is, a structure designed primarily for the use of humans, instead of telecommunications equipment. It stands at 1,483 feet (452 m.).

The Sears Tower was the World’s Tallest Building from 1973 to 1996. it stands at 1,454 feet (443 m). For a discussion on the debate over which of the two buildings is truly tallest, see

Noder comments

pimephalis says: You could also mention that there is a long standing tradition of comical stunts being performed in the annual 'climb the tower' charity. For example, two guys portaged a canoe to the top. Another wore his entire hockey goalie equipment, including skates, and made it to the top. There is also a race every year.


Being in it today, plus:

It's interesting to note that Toronto's CN Tower is basically a single piece of concrete up to the top. After the foundation was set the main column of the building was created by pouring concrete into a mold. Once the concrete had partially set, the mold was raised and more concrete was poured on. The concrete mold was brought up higher and higher as the base of the building set and concrete was poured continuously day and night until the CN Tower was complete up to the first observation deck. The concrete could never be allowed to dry completely as this would negatively affect the structural stability, which was of paramount concern for such a grandiose and risky design. This is how the CN Tower was made so quickly - in under four months! In the later stages of construction, concrete had to be brought up to the mold via helicopter. It's true!

Though the CN Tower may be The World's Tallest Free-Standing Structure, this is only because of that huge, meaningless spike at the very top, which seems to me was just tacked on near the end to make damn sure that it was indeed the tallest structure.

In fact, as you can see from the writeup above, its total height is 553m, but the highest a person could actually get is 447m, and most people just go up to the glass floor anyway, which is at 342m.

The CN Tower is also known for its ugliness. It has been said that it looks much like a donut stuck onto a Juno award (a Canadian award show, and thus largely unknown to the rest of the civilized world). Some people like to boast to live in the only building in Toronto not to have a view of the CN Tower.

Curiously enough, the CN Tower stands at the base of Yonge Street, which is currently The World's Longest Street, and right next to the SkyDome, which, as far as I remember, has the world's largest retractable roof. It's also located in Toronto, which is the world's most multicultural city. If only someone could combine these four feats into one... But HOW? HOW?

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