Meramec Caverns

Meramec Caverns is a 4.6-mile (7.4 km) cavern system in the Ozarks, near Stanton, Missouri. It formed over millions of years as water eroded large deposits of limestone, and Native American artifacts from before European contact have been found inside. Native peoples used the caves for shelter.

It is described as the most-visited cave in Missouri, with about 150,000 visitors a year. It is also a classic roadside stop, with more than fifty billboards along Interstate 44, and it is counted among the main attractions along the former U.S. Highway 66.

A French miner first visited the cave in 1722, making it the first cave west of the Mississippi River explored by Europeans. In the 18th century it was mined for saltpeter, used to make gunpowder. During the Civil War the Union Army ran a saltpeter plant here, until Confederate guerrillas found it and destroyed it. Local legend says Jesse James and his brother hid in the caves in the 1870s, but there is little historical evidence for it.

The longer cave system was found in 1933 and opened to the public in 1935 under Lester B. Dill, who is credited with inventing the bumper sticker to promote it. In 1960 the caverns rented out billboard space underground, and in 1972 they served as the cave setting for the musical film Tom Sawyer, released the following year.