1100 Superior (formerly known as the Diamond Shamrock Building, the Diamond Building, and Oswald Centre) is a skyscraper in downtown Cleveland, Ohio's emerging Nine-Twelve District. Built in 1972, it has 23 floors and rises to a height of 282 feet (86 m). It was designed by the firm of Skidmore, Owings and Merrill and is located at 1100 Superior Avenue at East 12th Street. In 1994, during a water main break, a four-story section of the Diamond Building lost some of its glass from pressure of the water. In 2012, the tower's naming rights were purchased by insurance brokerage the Oswald Cos., one of its largest tenants.