Vulcan's citadel

This citadel is in the lower levels of the Halls of Gold
On going through the huge double doors there is anvenormous cavern, a lake fills most of this, with a narrow causeway descending down to a fortress in the middle of the lake.
The cavern and lake are around 2 miles across,
The fortress in the middle is marked by pools and streams of molten lava.
There are ledges high above, with places that Ajax Firestorm, Red Dragon, Ancient uses to fly high above in the cavern.