New Zealand is not only magnificent from above! In certain areas where the soil is rich in limestone, cave systems form that offer adventurers a look deep into the earth. The best known area is Waitomo in the northern central region although there is also caving to be had else where on the West Coast and northern parts of the South Island.
Cave rafting (blackwater rafting), cave abseiling (rapelling), tubing, and walking are all different methods of exploring the caves, depending on the level of adventure sought.
Most caves are formed from limestone and marble sediment. Enormous amounts of calcium rich mollusc shells and skeletons of marine life form a thick strata, which over millions of years, compresses and solidifies. Over time, this sediment cements together to become rock
. As rainwater leaches through the soil, a mild solution of carbonic acid is released through cracks in the limestone, enlarging them. The drips also create other cave formations like stalactites. Over time, some passages erode to a large enough extent to become underground streams or rivers. As a result, a hidden world is created, a world of caves, sinkholes and complex shafts.