Most visited glowworm caves

Best known for the stunning bioluminescent displays put on by native glowworms (Arachnocampa spp.), the Waitomo Caves are a major tourist attraction located in the King Country region of New Zealand's North Island. With guided tours having taken place here since 1889, nowadays in a typical year, the caves attract between 450,000 and 500,000 visitors, with more than 2,000 a day attending in peak summer season.

The Waitomo Caves were first discovered in 1887 by Maori Chief Tane Tinorau and British surveyor Fred MaceIn. The specific species of glowworm found in this cave system, and throughout New Zealand, is A. luminosa; in Maori, it is known as titiwai ("projected over water").

Glowworms are the larval stage of a group of flies known as "fungus gnats". At this point in their lives, they dwell in damp, humid settings such as caves, tunnels and sheltered spots such as overhangs on river banks.

As with fireflies, a chemical reaction in their bodies is responsible for the ethereal blue-green light that they emit. Unlike fireflies, however, who use their natural light to attract a mate, glowworms use theirs as a means to catch prey. Each glowworm produces a series of mucus-studded filament or "fishing lines", which dangle below it; en masse. all of these spider-silk-like strands form a huge sticky web on the roof of a cave or tunnel. In the darkness, their bioluminescent bodies then fool moths, who rely on natural light to navigate, into thinking they are outside and seeing a star-studded night sky, only to fly upwards and find themselves entangled.

Although Waitomo's are the best known and most visited glowworm caves, glowworm tourism is a growing industry in several sites across New Zealand and in eastern Australia. The most popular example in Australia is Natural Bridge in Springbrook National Park in Queensland, which receives around 280,000 visitors per annum.