The Waitomo Caves system is over 250 kilometers in length and around 120 meters deep. The main cave, known as the Glowworm Cave, is approximately 1.6 kilometers long.
New Zealand
"Waitomo" in Maori means "water passing through a hole" or "water that flows into a cave" in reference to the underground rivers and caves in the Waitomo region of New Zealand.
In the North Island, it would be Waitomo Caves. In the South Island, there is a cave complex in Nelson region, and it contains Harwood's Hole, an exceptionally deep cave system, still being explored. Further south, at Te Anau, there are the Te Anau glow worm caves. Harwood's Hole is not a commercial venture, because of dangers and the level of experience needed. The Waitomo and Te Anau caves both have organized tours.
Caves can be found all over the world, in various environments such as mountains, deserts, and even underwater. Some famous cave systems include Mammoth Cave in Kentucky, the Caves of Cappadocia in Turkey, and the Waitomo Glowworm Caves in New Zealand.
Blackwater Rafting also called Cave Tubing is like whitewater rafting but in caves. It is especially popular in Waitomo, New Zealand.
I think you are enquiring about the underground cave systems. Either those of Waitomo in the North Island, or those of Te Anau Au of Lake Te Anau in the South Island. Both have well developed tourist industries.
Waitomo Glowworm Caves was created in 1889.
Waitomo Caves Hotel was created in 1908.
Hotels in Waitomo can be researched and reviewed on Travelocity, Expedia, Hotels, TripAdvisor, and the Waitomo Island official website. These beach side hotels are all very nice.
Deep, deep down
Waitomo Caves in New Zealand attract around 500,000 visitors each year.