Radio New Zealand tales from beneath the surface of the earth.
Professor David Pike studies underworld civilisations from Medieval times through to the present day, in fact and in fiction. He's a fan of New Zealand photographer Wayne Barrar's series of subterranean photographs.
A cave entrance in the Waitomo area. CC BY James Shook.
Simon Mercep digs deep with three experts on caves and caving.
GNS Science geologist Hamish Campbell explains why New Zealand has so many caves and how they are formed.
A chief guide for the Waitomo glow-worm caves Huia Davis talks about the value of caves (and glow-worms) for tourism in New Zealand.
Veteran cave explorer Kieran McKay's team discovered New Zealand's deepest cave system in the Kahurangi National Park in 2014.
Lower levels of Nettlebed Cave, New Zealand CC BY-SA 3.0 Dave Bunnell.
Extreme Ways by Moby
Night Call by London Grammar