Aon Center (Chicago) Aon Center (Chicago) The Aon Center (200 East Randolph Street, formerly Amoco Building) is a modern supertall skyscraper in the Chicago Loop, Chicago, Illinois, United States, designed by architect firms Edward Durell Stone and The Perkins and Will partnership, and completed in 1974 as the Standard Oil Building. With 83 floors and a height of 1,136 feet (346 m), it is the third tallest building in Chicago, surpassed in height by the Willis Tower, and the Trump International Hotel and Tower. The building is managed by Jones Lang LaSalle, which is also headquartered in the building. Aon Center formerly had
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