Mines

Mines are an underground bases you can build as you like. Just like normal bases.

You have to mine pieces of the ground/dirt and creating space for building(or not).

Every piece you mine will give biome corresponding resources if you have good enough pickaxe in use.

Stone, coal and some valuables are drops on every biome.

Also additional drops and foes can be found in

Meadows: flint, tin ore and copper ore. Some critters and skellies.

Black forest: Copper ore, tin ore and bronze scraps. Critters, skellies and ghost likes.

Higher tier biomes will offer better and more resource drops, but also can lure more dangerous foes.