The Yang-Dao Sect

As he stepped through the arched entrance, the Yang-Dao Sect finally came into view, no longer obscured by the dome of fire. 

He had been expecting the sect to be above him, continuing up the mountainside as the city outside did. That was not the case. Instead, before him was a massive caldera, like the mouth of a enormous fifty mile wide volcano in which the sect was built in. 

The walls of the caldera stretched upwards several dozen miles, and met perfectly with the dome of fire, making the interior look like a massive sphere, half of fire, half of earth. 

Dozens of rivers of molten lava flowed down from where the dome met the earthen walls, flowing down to the basin below. The rivers collected in a lake of scorching lava, atop which the Yang-Dao Sect was built.