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
Metropolitan Tower (Chicago) of this ornament, the building is sometimes referred to as the "Beehive Building." Just beneath the beehive are four carillon bells ranging in weight from 1,500 to 7,000 pounds, unused for many years until restored in 1979 for the Chicago visit of Pope John Paul II. At one time, the bells chimed the well-known Cambridge Quarters on the quarter-hours. The base has been altered from its original design: rectangular window openings replaced giant arches on Michigan Avenue and Jackson Boulevard. At one time, the thirtieth floor was the Straus Tower Observatory, which was open to the public for viewing the