Cave in New Zealand hides a secret that does not exist anywhere else on the planet.

In the depths of limestone caves of New Zealand settled a colony of special fireflies. They emit a soft blue-green light, enough to illuminate the cave walls. These little creatures are called Arachnocampa luminosa. Here are photos of this phenomenon made by Joseph Michael.

• Blue caves
• 15 The most adorable caves
• Natural phenomena that are breathtaking