Terra Cotta, California
Coal, along with clay deposits, was found on the site by John D. Huff in the late 1880s, and the Southern California Coal and Clay Company was formed to mine them. The town site of Terra Cotta was laid out and was given a post office on October 26, 1887. In May 1893 its post office was closed and moved to Lake Elsinore. A plant for the manufacture of sewer and water pipes was built using the coal to fire ceramic pipes in the four kilns. The finished product had to be shipped by wagon six miles through Lake Elsinore to the La Laguna rail station at the mouth of Railroad Canyon until 1896 when a spur line was built through Lake Elsinore and Terra Cotta to the new clay deposits in Alberhill. The coal mined was also used locally as fuel for the stamping mill at the Good Hope Mine and was shipped elsewhere in the state.
Slănic mine
Slănic mine is an old salt mine, located in Slănic, Prahova County, Romania, just 100 km north of Bucharest. The salt mine is closed for extraction purposes, but is open for visitors, featuring a microclimate with natural air-conditioning and constant temperature and atmospheric pressure throughout the year. It is made up of two levels, named "Unirea" and "Mihai". Many of the visitors come for its supposed healing effects due to the purity of the air. Throughout the mine you will find various types of equipment for recreational activity such as playground equipment and some ping-pong tables. One area is sectioned off and is being used for medical patients with lung cancer to come and rest. The main elevator shaft is unique in that it has no metallic parts due to rust. After an elevator accident in 2014, minivans are used to spiral visitors up and down.