Strataca

Strataca, also known as Kansas Underground Salt Museum, is located in Hutchinson, Kansas, United States. It is built within one of the world’s largest deposits of rock salt and provides the opportunity to go 650 feet (200 m) beneath the Earth’s surface. It is a unique destination attraction for exploring an environs carved from salt deposits formed 275 million years ago. 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 none of them are accessible to tourists.

• http://en.wikipedia.org/wiki/Strataca