Tulsa includes many structures built during the Oil Boom in the 1920s and 1930s, including Art Deco buildings such as the Midcontinent Tower, Boston Avenue Methodist Church, and the Exchange Bank Building (today known as the 320 Boston Building). Oilman Waite Phillips, left a significant architectural impact on downtown Tulsa through the Philtower and Philcade buildings. Other notable Tulsa buildings include the Atlas Life building, Christ the King Catholic Church, Holy Trinity Greek Orthodox Church, and the Mayo Hotel, the former of which once served as home to J. Paul Getty. Known for a time as "Terra Cotta City", Tulsa hosted the International Sixth Congress on Art Deco in 2001.
Downtown Tulsa is in the northwest quadrant of the city and is ringed by an expressway system called the inner dispersal loop. Downtown's buildings include many large office towers. At 667 ft (203 m), the BOK Tower (formerly One Williams Center) is the tallest building in any of the 5 "plains states" (Oklahoma, Kansas, Nebraska, North Dakota and South Dakota) and was designed in 1975 by Minoru Yamasaki & Associates, the same architect who designed the World Trade Center in New York.
The Tulsa Performing Arts Center occupies a half city block in Tulsa's historical downtown. The PAC is also the design of Minoru Yamasaki. It houses five theatres and a reception hall. More than a quarter of a million people visit the Center each year to attend a performance from one of Tulsa's seven acclaimed musical and dramatic companies including the Tulsa Ballet, Tulsa Symphony Orchestra, Tulsa Opera, and a variety of symphonic groups. The PAC hosts a multitude of cultural events through the fall, winter and spring.