Strataca

Strataca is a salt mine museum in Hutchinson, Kansas, United States. It was previously known as the Kansas Underground Salt Museum. The museum is built within one of the world's largest deposits of rock salt, formed 275 million years ago, and provides the opportunity to go 650 feet beneath the Earth’s surface. The museum is located in the Hutchinson Salt Company mine which began operation in 1923 as Carey Salt Company. There are 14 other salt mines in the United States, but Strataca is the only one accessible to tourists.

Source: Wikipedia