The algae filaments bore their way into the limestone and in turn create this black organic coating that protects them and their host rocks from sunlight and other natural elements. Surprising it is, to think that most of this landscape was once white limestone before it became consumed by the algae. The algae have such a strong influence on the limestone that they actually dissolve much of the stone in their effort to protect themselves, obtain metabolic carbon, or obtain a damper tunnel environment for which they can better hold capillary water. Phytokarst environments are believed to exist mostly in places with high humidity and tropical climates, such as Grand Cayman, though they are also known to exist in caves and other limestone-rich environments.
So, you can go to Hell… At least if you want to see an interesting relationship between tiny algae filaments and natural limestone. Quite cautious they are in Hell, protecting visitors from the sharp and edgy phytokarst limestone, only letting them view the pinnacles from a safe distance. On your way out, be sure to stop by the Visitor’s Office and pick up a few postcards for friends and relatives, proving that you have been to Hell and back.