Nettlebed Cave

Nettlebed Cave is a limestone cave located in the Mount Arthur region of the northwest South Island of New Zealand. The presence of ongaonga (Urtica ferox), an endemic tree nettle, near the bottom entrance gives the cave its name. Nettlebed Cave was connected to Stormy Pot in January 2014, making the system the deepest known cave in the Southern Hemisphere. Nettlebed Cave drops 1,180 metres (3, 870 ft) below its upper entrance (Big Friendly Giant, Stormy Pot) to its lower exit (the Pearse River resurgence) and is 48 kilometres (30 mi) long.

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).