Great Furnace

"The Great Furnace was not as big or imposing as the Coliseum in the center of Metru Nui. It did not have the feeling of power and mystery that Ga-Metru's Great Temple possessed. But every Ta-Matoran looked at it with awe and wonder. It was a symbol of what made the metru great - the power that turned solid protodermis to molten liquid, and the skill to shape that raw material into the tools Matoran used every day."

- Narrator, Trial by Fire

The Great Furnace is the largest and most prominent furnace in the Ta-Metru district of Metru Nui.

History
The Great Furnace was constructed early in Metru Nui's history and served functionally for many thousands of years. Inside, temperatures were so high that Ta-Matoran could not work for extended periods of time. It was here that flawed Protodermis creations are melted down for later recasting.

During the Morbuzakh attacks, the King Root established a permanent residence in the Great Furnace, forcing the Furnace Salamanders living there to seek a new domain. Seeking to conceal the source of the destructive plant, Makuta Teridax, disguised as Turaga Dume, denied access to the Great Furnace. He created the excuse that the Furnace was closed for renovations and assigned several squads of Vahki to guard it against intruders.

Through her studies of Morbuzakh behavior, the Ga-Matoran student Vhisola correctly guessed that the plant thrived on heat and imparted this insight to Toa Metru Nokama. Mobilizing the rest of the Toa Metru and their Matoran partners, the assembled party traveled to the Great Furnace with the Great Disks she had collected to confront the King Root.

The Toa Metru left the Matoran outside to defend their exit, and the Matoran formed a Matoran Nui to combat the vines. The Toa ventured inside to attempt to defeat the King Root. After nearly defeating them, the power of the Great Disks created an energy sphere that imploded, destroying the Root and ending the Morbuzakh's threat. The implosion reduced the Great Furnace to rubble and had gained further damage by the Great Cataclysm and the raid of Visorak.

A thousand years later, after the Matoran returned from Mata Nui, Jaller became frustrated with the Turaga for being untruthful concerning the absence of the Toa Nuva. Later he ordered that all repairs being made towards the ruined city be stopped and the Matoran retaliated by going on strike. While sitting in the Great Furnace, Nokama approached the Captain of the Guard and told him the truth about the Toa Nuva and their journey to Voya Nui.

The Great Furnace was partially rebuilt by the Matoran after their return to Metru Nui, and later completely restored by the usage of the Staff of Artakha.

Later, the Order of Mata Nui spread rumors through servants on Stelt that they had converted the Great Furnace into a Virus factory so that could recreate the Protosteel-eating virus that killed Makuta Kojol, thus making Metru Nui a bigger target for the Brotherhood of Makuta.

The Great Furnace, like the rest of Metru Nui, was severely damaged when a fragment of Aqua Magna struck the head of the Great Spirit Robot during Teridax's battle with Mata Nui.

It was evacuated after Spherus Magna was reformed.

The Kingdom Alternate Universe
In this alternate universe, the Great Furnace was rebuilt in the island of Mata Nui, and was where Toa Mahri Jaller spent most of his time.

Trivia

 * There was an online game called Stop the Morbuzakh, in which the player (Vakama) was defending Ta-Metru from the Morbazakh.