The World of Virtual Reality

This dungeon looks different from the Moon Dungeon - the outer part is not the moon, but a normal one like an ordinary old building.
The first floor looks like a labyrinth with dark walls made of stones measuring 50x50x50, it has already been fully explored.
The second floor looks completely different from the first: it's an endless forest with trees such as palms, oaks, and, further north, pines and spruces. 1,000 km to the north, west, and east have been explored. No one has yet ventured south due to abnormal heat 5 km to the south.
The other floors are also not similar to each other, at least according to the S-rank mercenaries, because no one except them has gone below the 2nd floor yet - due to fear of the unknown.

This dungeon looks like the moon (the exterior)—the entrance literally looks like a moon made of glass, beyond which nothing can be seen. The Moon Dungeon has been around for a long time—from 100 to 286 years—but it remains popular.