Bohrok Nest

The Mata Nui Bohrok Nest was the place where the Bohrok slept until Teridax awakened them earlier. It was connected to Mangaia. All the Bohrok and Bohrok Va came from it. It was the home of the Bahrag as well.

History
The Bohrok Nest was created by the Great Beings, as part of the Great Spirit Robot. The purpose of this nest was to house the Bohrok until they were needed to clear the island that would form over the robot's face before it headed off for another planet.

While on the way back to Metru Nui, The Toa Metru found the Bohrok Nest. Because of this, they hid warning signs on various parts of Mata Nui.

The nest was discovered by Takua, who managed to sneak into the chamber behind Teridax's lair in Mangaia. Teridax caused the Bohrok to awaken early, and Takua thought it to be his fault. Takua then escaped the nest.

The Toa Mata, after collecting 48 Krana, eight from each Bohrok, descended into the nest. By inserting the Krana into special niches, they discovered machines known as Exo-Toa, which they could pilot. The Toa Mata then went to fight the Bahrag, but were unable to channel their elemental powers while using the Exo-Toa suits. They then abandoned the armor and combined their elemental powers, creating a seal around the Bahrag, which could be broken through an object called the Nuva Cube. The Toa were then forced into tanks of Energized Protodermis, which transformed them into Toa Nuva.

After the Bahrag were defeated and the Toa left, an avalanche covered the entrance, but Pahrak-Kal uncovered the entrance. The Exo-Toa went on auto pilot and fought the Kal, but to no avail. They were just about to put in the Toa Nuva's Nuva Symbols when the Toa arrived and defeated them.

Trivia
There was also a Metru Nui Bohrok Nest, but it contained minute amounts of Bohrok compared the the Mata Nui nest. Krakua awakened the Bohrok there.

Geography
The nest was in Mount Ihu. The entrance tunnel eventually led to a chamber with an opening that led to the heart of the nest. However, this room was destroyed by Tahu.

Far underneath the heart of the nest was the Bahrag's chamber, which contained 48 niches for Krana to fit in. There were six passageways, each with Exo-Toa armor inside. There were also six tubes full of Energized Protodermis in the chamber.

The entrance tunnel just led to an opening to the Bahrag's chamber, though there was a sharp drop to the ground. There was a cube floating in the center that contained the Bahrag. It wasn't destroyed because it was a part of Mata Nui.