Great Chamber of the Senatorum Imperialis
Built as the original seat of Imperial power on humanity's throneworld, the temple is used as the "parliament" of the Imperium. Capable of holding over a million people, it is the most well known meeting place of the Senatorum Imperialis. The chamber itself is designed as a Colosseum, at the center of which sits a great dais where the Twelve High Lords of Terra sit. At the order of Roboute Guilliman, a huge statue of Rogal Dorn was erected at the east end. While the chamber is the most famous meeting place for the High Lords, they will often use other, smaller locations.