Tulsa is the second-largest city in the state of Oklahoma. It has many diverse neighborhoods due to its size. Downtown Tulsa is an area of approximately 1.4 square miles (3.6 km2) surrounded by an inner-dispersal loop created by Interstate 244, Highway 64, and Highway 75. The area serves as Tulsa's financial and business district, and is the focus of a large initiative to draw tourism, which includes plans to capitalize on the area's historic architecture. Much of Tulsa's convention space is located in downtown, such as the Tulsa Performing Arts Center, the Tulsa Convention Center, and the BOK Center. Prominent downtown sub-districts include the Blue Dome District, the Brady Arts District, the "Oil Capital Historic District", the Greenwood Historical District, Owen Park Historical Neighbor