 At , the BOK Tower (formerly One Williams Center) was the tallest building in any of the 5 "plains states" (Oklahoma, Kansas, Nebraska, North Dakota and South Dakota) until the Devon Tower in Oklahoma City was completed in 2012.The BOK Tower was designed in 1975 by Minoru Yamasaki & Associates, the same architect who designed the World Trade Center in New York City.The Tulsa Performing Arts Center occupies a half city block in Tulsa's historical downtown.