In recent years, about 1% of the Monument's 400,000 annual visitors climb Devils Tower, mostly through traditional climbing techniques. Film director Steven Spielberg used the location in his 1977 film Close Encounters of the Third Kind. Devils Tower was the first declared United States National Monument, established on September 24, 1906, by President Theodore Roosevelt. The Monument's boundary encloses an area of 1,347acres (5.45Square kilometers). Devils Tower is an igneous intrusion or laccolith located in the Black Hills near Hulett and Sundance in Crook County, northeastern Wyoming, above the Belle Fourche River. It rises dramatically 1,267feet (386m) above the surrounding terrain and the summit is 5,112feet (1,558m) above sea level.