This concrete communications and observation tower in downtown Toronto, Canada stands at 1,815 feet (553 m). When it was completed in 1976 it was the world’s tallest free-standing structure. The CN Tower is a symbol of Canadian achievement and in 1995 it was declared one of the modern Seven Wonders of the World by the American Society of Civil Engineers.
The Leaning Tower of Pisa, known worldwide for its unintended tilt to one side, is the freestanding bell tower of the cathedral in the Italian city of Pisa. Work on the ground floor of the white marble campanile began on August 8, 1173.
Big Ben is the nickname for the great bell of the clock at the north end of the Palace of Westminster in London though today the name also refers to the clock and the clock tower. The bell weighs almost 14 tons and each clock face is 23 feet in diameter. It became fully operational on September 7th, 1859 and is today one of the most prominent symbols of London standing at 316 feet high. The clock requires winding three times per week and pennies are periodically added or removed from the clock of pendulum to maintain its accuracy.
Located on the Champ de Mars in Paris, the Eiffel Tower has become a global icon of France and one of the most recognizable structures in the world. Named after its designer, engineer Gustave Eiffel, the tower was built as the entrance arch to the 1889 World’s Fair and stands at 1,063 feet tall. It was the tallest man-made structure in the world until the Chrysler Building was built in 1930.
Willis Tower is a 108-story, 1,451-foot (442 m) skyscraper in Chicago, Illinois. At the time of its completion in 1973, it was the tallest building in the world, surpassing the World Trade Center towers in New York, and it held this rank for nearly 25 years.