Sears conglomerate during the mid-20th century, adding Dean Witter and Coldwell Banker real estate in 1981, starting Prodigy as a joint venture with IBM in 1984, and introducing the Discover credit card in 1985. In 1974, Sears completed the 110-story Sears Tower in Chicago, which became the world's tallest building, a title it took from the former World Trade Center towers in New York. Sears moved to the new Prairie Stone Business Park in Hoffman Estates, Illinois, between 1993 and 1995. The Sears Centre is a 10,001-seat multi-purpose arena located in Hoffman Estates adjacent to the Prairie Stone campus. Even though
Park Tower (Chicago) Park Tower (Chicago) Park Tower is a skyscraper located at 800 North Michigan Avenue in Chicago, Illinois. Completed in 2000 and standing at tall with 70 floors — 67 floors for practical use, it is the twelfth-tallest building in Chicago, the 43rd-tallest building in the United States, and the 83rd-tallest in the world by architectural detail. It is one of the world's tallest buildings to be clad with architectural precast concrete (the Transamerica Pyramid Building in San Francisco is taller). It is one of the tallest non-steel framed structures in the world—it is a cast-in-place concrete framed structure. This building