A statue of Wichita Indians marks the crossing of the Wichita River where a 54-foot waterfall now welcomes visitors to Wichita Falls. The adjacent River Bend Nature Center showcases native ecosystems in a 7,000 square-foot glass structure and 17-acre wetland. Ranching, railroading and petroleum gave Wichita Falls wealth and is still reflected in several historic districts. The Depot Square Historic District includes oil boom skyscrapers, plus an oddly-narrow building featured in Ripley’s Believe It or Not as the world’s littlest skyscraper. Wichita Falls is a city of museums. Visual arts shine at Midwestern State University’s museum and gallery, as well as the Kemp Center for the Arts in a 1916 library. Performing arts captivate audiences at the Wichita Theatre, housed in 1908 opera house. The Kell House Museum details the lifestyle of a prominent early family. The Wichita Falls Railroad Museum features period rolling stock, and the Wichita Falls Fire & Police Museum displays antique vehicles. Exhibits at the Museum of North Texas History range from cowboy hats to military uniforms. A small museum at Kickapoo Airport maintains a rare flyable Curtiss JN4-D "Jenny" biplane used in World War I at Call Field. Finally, the 1928 Kell Field Air Terminal at Sheppard Air Force Base chronicles military aviation.