CN Tower

The CN Tower (French: Tour CN) is a 553.3 m-high (1,815.3 ft) communications and observation tower in Toronto, Ontario, Canada. Completed in 1976, it stands in downtown Toronto on the former Railway Lands. Its name "CN" comes from Canadian National, the railway company that built it.

For many years, the CN Tower was the world's tallest free-standing structure. It held this record for 32 years, from 1975 until 2007, when it was surpassed by the Burj Khalifa. It remains an important landmark and one of the modern Seven Wonders of the World, as chosen by the American Society of Civil Engineers.

Today, the CN Tower is a famous symbol of Toronto's skyline. It welcomes over two million visitors each year. People come to enjoy its observation decks, a special revolving restaurant high above the ground, and other fun attractions.

History

The CN Tower was first imagined in 1968 when the Canadian National Railway wanted to build a tall tower for television and radio signals in Toronto. They wanted to show how strong Canadian industry was. As Toronto grew, new tall buildings made it hard for radio and television signals to reach everyone well. The tower would help solve this problem.

Construction of the CN Tower began in 1973. Workers dug deep into the ground to build strong foundations and then built the tall tower using special methods. The tower opened to the public on June 26, 1976. It became one of the most famous landmarks in Toronto and attracted many visitors. Over the years, new attractions like a glass floor and a walk around the edge of the tower were added to entertain people.

Closures

The CN Tower was closed on September 11, 2001, after big events happened in New York City. It was also closed during a big meeting of leaders in June 2010 for safety reasons. The tower stayed closed from 2020 to 2021 because of health rules during a sickness spreading around the world. One day in December 2021, the tower had to close because glass was falling off in strong winds.

Structure

The CN Tower is made up of several parts. The main part is a tall, hollow concrete pillar shaped like a hexagon. Inside this pillar are stairwells and pipes for electricity and water. The tower has six elevators, placed in the spaces between the sides of the hexagon. These elevators have glass walls, so you can see the city as you ride up.

At the top of the concrete part of the tower is a very tall metal antenna. This antenna sends out TV and radio signals. There are three places where visitors can go:

• the Lower Observation Level, which has a special glass floor and an outdoor area,
• the Main Observation Level, and
• The Top, which is just below the antenna.

The tower’s shape changes near the top, and below the main levels, there are three big legs that make it look like a tripod.

The main level of the tower has seven floors, some of which are open to the public. Below the public areas is a large round structure that holds transmitters. The glass floor can hold a lot of weight and has special thermal glass that keeps it warm. There is also a restaurant that slowly turns around as you eat.

The Top used to be the highest place you could go in the world, but another tall building in Shanghai passed it in height in 2008.

There is a very tall metal staircase inside the tower, used mostly for emergencies or special events. It has over 1,700 steps to reach the main level and more than 2,500 steps to reach The Top. It is the tallest metal staircase in the world.

Architects

• WZMH Architects
• John Hamilton Andrews
• Webb Zerafa
• Menkes Housden with the help of Edward R. Baldwin

Safety features

After a fire in a similar tower in Moscow, officials checked the CN Tower carefully. They found that the CN Tower has many safety features to prevent fires, like fireproof materials, frequent inspections, a good sprinkler system, and special water tanks at the top. There is also a special elevator that can work during a fire and is powered by generators at the base. These safety measures help keep the tower safe.

The CN Tower has had a very good safety record, with only one small electrical fire in its antennas in 2017, which was the tower’s first fire. Other tall buildings built around the same time also have strong safety records, showing that serious accidents like the one in Moscow are very rare.

Lighting

The CN Tower was first lit at night with special lights that were later replaced in 1997 because they used too much energy. In June 2007, the tower got new, super-bright LED lights that shine from dusk until 2 a.m. These lights use much less energy and can change colors for special events.

The tower’s lights often change colors for holidays and important moments. For example, after big sports events, it might show the colors of the winning team. It has also shown the colors of flags from other countries to honor special people or events. The lights are controlled from a computer far away and cost about $1,000 each month to run.

During spring and fall when birds are flying across the sky, the lights are turned off to help keep birds safe. This is part of a program that asks tall buildings to dim their lights during busy bird travel times.

Height comparisons

The CN Tower is the tallest freestanding structure in the Western Hemisphere. As of 2013, two other freestanding structures in the Western Hemisphere were taller than 500 m: the Willis Tower in Chicago and One World Trade Center in New York City. The CN Tower remained the tallest freestanding structure in the Western Hemisphere for many years.

There has been some debate about whether the CN Tower is the "world's tallest tower" or the "world's tallest building." Organizations like Guinness World Records and others have different ways to define these titles. The CN Tower does not have floors all the way from the ground up, so some groups do not call it a true building. Instead, they call it a "tower." Other very tall structures, like radio masts, are not considered "free-standing" because they are supported by wires. The CN Tower was the tallest freestanding structure in the world until 2007 when Burj Khalifa in Dubai passed its height. Even after that, the CN Tower still holds several records, such as the highest wine cellar and restaurant above ground.

Use

The CN Tower serves as an important communications tower for many different media companies and services.

There are no AM radio broadcasts from the CN Tower. FM radio transmitters are placed in a tall metal antenna on top of the tower, high above the ground.

See also: List of radio stations in Ontario

• Bell Canada
• Toronto Transit Commission
• Amateur radio repeaters "2-Tango" (VHF) and "4-Tango" (440/70 cm UHF)—owned and operated by the Toronto FM Communications Society, under callsign VE3TWR

In popular culture

The CN Tower has appeared in many movies, TV shows, music covers, and video games. It even has its own mascot that looks like the tower.

Some examples include the 1982 movie Highpoint, the 2016 album Views by Drake, and the 2025 film Nirvanna the Band the Show the Movie. These works showcase the tower in exciting and creative ways.