As they entered the second hall, Jason noticed that it was even bigger than the first hall they had been in and by a huge margin at that.
It was a gigantic underground city with large compressed-stone compounds that were connected with wooden suspension bridges.
In the middle of the underground city, one could see a huge natural water stream, separating a hundred-meter-high building from the rest of the city. It almost looked like the buildings made for higher nobles.
At least, similar valuable materials were used to build it and Jason could see mana radiating around the whole building.
However, much more important was what he saw inside the building.
Jason was still not extremely proficient with his mana eyes and he wasn't able to look through too many stone layers or rather materials with larger amounts of mana inside.
Creation is hard, cheer me up!