Crystal Cave

Crystal Cave is a fairly big cave under the Tohunga Village created by Protodermis Matoran as his home. It's wall's were made of different kinds of crystal and protodermis along with Lightstones that gave light to the cave. The cave had a few rooms in it. Atleast one, quite big hall was made. Then there were a few rooms which the Protodermis Matoran lived in.

History
Protodermis Matoran created the Crystal Cave soon after he was created and put to Bio-Land by Mata Nui. Protodermis Matoran decided to build it under the Tohunga Village so he could observe them without being noticed.

Protodemris Matoran spent thousands of years in the cave. When, during Piraka Attack, The Toa Nuva were fighting the Piraka on the village, Protodemris Matoran captured Takanuva in the cave and took him into a big hall where he trained him for combat. After that he left to help the good guys against the Piraka. After that he didn't return to his cave but instead went somewhere else.

The Crystal Cave is currently deserted, but Protodemris Matoran will return there after he has helped Henkka.

Trivia

 * There is a room in the cave, where the things above the surface, in the Tohunga Village can be seen through a big crystal.