The Waitomo Glowworm Cave is on the North Island of New Zealand, known for its population of glowworms. These glowworms are found exclusively in New Zealand and around the size of an average mosquito. A tour through the cave concludes with a boat ride through the Glowworm Grotto. The boat takes the visitor onto the underground Waitomo River where the only light comes from the tiny glowworms creating a sky of living lights.
Source ; http://slightlywarped.com