English: Timpanogos Cave National Monument is a United States National Monument protecting the Timpanogos Cave Historic District and a cave system on Mount Timpanogos in the Wasatch Mountains in American Fork Canyon near American Fork, Utah, in the United States. The site is managed by the National Park Service. The 1.5-mile (2.4 km) trail to the cave is steep, gaining close to 1,000 feet (300 m), but paved and fairly wide, making the caves accessible to most. The three caves of the system, one of which is specifically called Timpanogos Cave, are only viewable on guided tours when the monument is open, usually from May through September depending on snow conditions and funding. There is the standard tour going through the cave system, and an Introduction to Caving tour which teaches Leave No Trace caving and goes further into Hansen Cave. The three caves of the Monument that are tourable are: Hansen Cave, Middle Cave, and Timpanogos Cave. The three caves are connected by manmade tunnels blasted in the 1930s by the Works Progress Administration . The average temperature in the caves is 46 degrees Fahrenheit. Many colorful cave features or speleothems can be seen. Among the most interesting are the helictites, which are hollowed, twisted, spiraling straws of deposited calcite or aragonite. They are formed when water travels through the tube and then evaporates, leaving a trace mineral deposit at the end. Other speleothems found in the cave include: cave bacon, cave columns, flowstone, cave popcorn, cave drapery, stalactites and stalagmites.