The Willis Tower Skyscraper in Chicago, IL was built in August 1970. The building was finished in 1973. It was the tallest building in the world from 1973 to 1996. The Willis Tower Observation Deck AKA The Skydeck was opened on June 22, 1974. It is located on the 103rd floor with an elevation of 1,353 feet or 413.4 meters. It is the highest observation deck in the United States, also one of Chicago's most famous tourist attractions.
Construction started in 1970 and got over by 1973. Skydeck was added in 1974.
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