CN Tower fire. Moreover, other supertall structures built between 1967 and 1976 — such as the Willis Tower (formerly the Sears Tower), the World Trade Center (until its destruction on September 11, 2001), the Fernsehturm Berlin, the Aon Center, 875 North Michigan Avenue (formerly the John Hancock Center), and First Canadian Place — also have excellent safety records, which suggests that the Ostankino Tower accident was a rare safety failure, and that the likelihood of similar events occurring at other supertall structures is extremely low. The CN Tower was originally lit at night with incandescent lights, which were removed in 1997, because
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