Walking to the center of the underground space, Gu Xi looked up and just saw the passage that went straight up and down.
The passage was incredibly large.
Looking up from a position more than sixty meters from the passage, one could still see a massive pipeline with a diameter of over forty meters.
With the size of this passage, two to three Giant Dragons could fly side by side without any issue.
Looking further up, you could even see a bit of sunlight falling in from above.
It was very clear that this passage led directly to the outside of the castle above.
All the Giant Dragons could fly out from here, while the sunlight and rainwater from the ground could also fall into the underground space from here.
Right below this passage was the massive maze.
Unlike the maze between the City Walls seen earlier.
The maze ahead was entirely made of a type of Black square brick.
These square bricks were obviously much thicker than the yellow bricks on the ground.
