An ancient sanctuary hidden in Vulcan's Forge that served as the Syrrannites' refuge in 2154 and was bombarded on the orders of Administrator V'Las.
The T'Karath Sanctuary is a complex of caverns and old chambers deep in the desert region of Vulcan known as the Forge. It appears in the Enterprise episodes Awakening and Kir'Shara.
In 2154 it shelters the Syrrannites, a group who follow what they hold to be the true teachings of Surak and who are blamed for the bombing of Earth's embassy. Archer and T'Pol reach it after crossing the Forge, and find T'Pau and T'Pol's mother T'Les there. Archer, who carries Surak's katra, is led by it to the Kir'Shara, an artefact holding Surak's original writings.
V'Las orders the sanctuary bombed from orbit to destroy the movement. T'Les is killed in the attack, but Archer, T'Pol and T'Pau escape with the Kir'Shara.