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This seven wonders list, chosen by the American Society of Civil Engineers, celebrates monumental engineering and construction feats of the 20th century.

the Golden Gate Bridge at sunset the Golden Gate Bridge at sunset

 

Wonder Description
1. The Empire State Building The Empire State Building in New York was finished in 1931. It is 1,250 feet tall, and until the first tower of the World Trade Center was finished in 1972, it was the world's tallest building.
2. Itaipú Dam The Itaipú Dam built by Brazil and Paraguay on the Parana River is the world's largest hydroelectric power plant. It was completed in 1991, and took 16 years to build. It is composed of a series of dams whose length totals 7,744 meters. It used 15 times more concrete than the Channel Tunnel.
3. CN Tower In 1976,the CN Tower in Toronto, Canada, became the world's tallest freestanding structure. It is about one-third of a mile high (1,815 feet). A glass floor on the observation deck lets you look 342m down to the ground.
4. Panama Canal It took 34 years to create this 50-mile-long canal across the Isthmus of Panama. The amount of digging required and the size of its locks helped make it the most expensive project in American history at that time. It was also a deadly project about 80,000 people died during construction (mostly from disease).
5. Channel Tunnel The Channel Tunnel, also known as the Chunnel, links France and England, across the English Channel. It is 31 miles long, and 23 of those miles are 150 feet beneath the seabed.
6. North Sea Protection Works Because the Netherlands is below sea level, a series of dams, floodgates and surge barriers have been built to keep the sea from flooding the country during storms. The biggest part of the project was a two-mile long moveable surge barrier across an estuary finished in 1986. It is made of 65 concrete piers each weighing 18,000 tons. It has been said that the project is nearly equal in scale to the Great Wall of China.
7. Golden Gate Bridge The Golden Gate Bridge in connects San Francisco and Marin County. Built in 1937, for many years this was the longest suspension bridge in world. Experts thought that winds, ocean currents and fog would make it impossible to build. It took about four years to complete and it is held by 80,000 miles worth of steel wire, and the cables that link the two towers are 36.5 inches in diameter.

see also the 7 ancient wonders, 7 natural wonders, the 7 new wonders of nature and the 7 new wonders

 

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