The One World Trade Center (or Freedom Tower) is the main building of the new World Trade Center complex in Lower Manhattan, New York City. The building is 1,776Â feet tall and is designed by David Childs of Skidmore, Owings & Merrill. Since late 2013, it is the tallest building in the United States. It opened in late 2014. It is mostly used for offices. People can view the city from an observatory near the top.

Willis Tower is a skyscraper in Chicago, Illinois. Sears, Roebuck & Company paid for it to be built in August 1970. The building was finished in 1973. It was the tallest building in the world from 1973 to 1996. It has 110 levels.^[2] From the ground to the roof it is 442 meters (1,450 feet) tall. It was designed by Fazlur Khan and Bruce Graham.

Willis Tower is the second-tallest building in the United States. It is the eighth-tallest freestanding structure in the world. It is the 12th tallest skyscraper in the USA. It is one of the most popular tourist destinations in Chicago. More than one million people visit its observation deck every year.

John Hancock Center is a skyscraper in Chicago, United States. It is 344 meters (1,127 feet) tall and has 100 floors, including an observation deck on the 94th floor (1,000 ft).^[1] It was built in 1969 and is one of the tallest buildings in the world