Oregon Caves National Monument and Preserve protects a marble cave and surrounding mountain landscape in southwestern Oregon near the California border. Discovered in 1874 by Elijah Jones Davidson, the cave drew early tourism efforts that failed before federal protection arrived in 1909 under President William Howard Taft. The cave is notable as a solutional cave formed in marble, with underground water flowing through it as the River Styx and emerging as Cave Creek; in 2014 this stream became the only subterranean river in the National Wild and Scenic Rivers System. Expanded that same year, the site is valued for cave tours, historic rustic architecture, significant fossils, and forested preserve lands.