Chevé Cave
Chevé Cave ( ; ) is a deep cave located in the Sierra Juárez mountain range in the southern Mexico state of Oaxaca. As of 2003, its deepest point has been measured at deep, making it the second deepest known cavern in the Western Hemisphere and the world’s 12th deepest cave. The cave's deepest known point is nearly one vertical mile and seven horizontal miles from the entrance, ending in a terminal sump. The present limit of exploration in Chevé, at 9.3 kilometers from the nearest entrance, represents one of the most remote locations ever attained inside any cave on Earth. The logistics of reaching this point are enormous: more than two kilometers of rope need to be rigged and three underground camps established. Chevé is the deepest proven freshwater hydrological system in the world. Temperatures in Chevé are moderate, ranging from . It has been most thoroughly explored under the leadership of caver Bill Stone.
Harz
Geomorphological processes have led to the formation of caves in the gypsum, dolomite and limestone layers of the Harz. These dripstone caves include Baumann's Cave, the Unicorn Cave, Hermann's Cave, the Iberg Dripstone Cave and, on the southern edge of the Harz, the Heimkehle.
Because the older formations contained many mineral deposits, they were explored very early on by the mining industry. The mines have often been turned into show mines. For example, the Samson Pit was for a long time the deepest mine in the world. Other show mines are the "Büchenberg", "Drei Kronen & Ehrt", the "Röhrigschacht" show mine, the "Lange Wand" show mine in Ilfeld and the "Rabensteiner Stollen" show mine in Netzkater.
Others have been turned into mining museums, like the Upper Harz Mining Museum in Clausthal-Zellerfeld, the Lautenthal Mining Museum with its pit railway or the Rammelsberg Mining Museum near Goslar, which is a UNESCO world heritage site. The Roter Bär Pit in St. Andreasberg also served as a training mine until the 20th century and is today, preserved true to the original, as a visitor mine.