A spiderweb of caverns that were created during the first continental divide, the caves were discovered by a famous explorer named Tukiyomi. These caverns connect the Western Continent to Antalya by running underneath the Goat Bay. It is still unknown how many of them exist, as many of them have filled with water over time. On the Antalya side, they are often called the Pandora Caves.
The caves are home to all kinds of poisonous monsters and fungi. Parts of it glow in the dark, but the ground is often unlevel and unpredictable.
The most famous caverns are the expansive Nameless Corridor, that allows you to travel between the continents in both Monster Rancher EVO and Monster Farm Lagoon. It is a possible ranch location in My Monster Rancher.