With Ancient Caverns you find a complete tool for your natural underground environment. It comes with over 180 prefabs including different big blocks to create custom rooms and also premade rooms to make it easier. Just add different details from rocks to stalactites, manmade stuff, candles, fungus, etc. Blocks are made to fit among them with a few clicks.
You can also use it as FPS or Top/Down environment since rooms are made of separate pieces so you can remove roofs whenever you want.
Check out [ASSET INFO] link above for extended info.
details:Total file size 1.6 GB
Number of files 788
Releases current ver. 1.0.1
released Mar 21, 2018
Original released Dec 28, 2017
Supported Unity versions 5.6.3 or higher
Package has been submitted using Unity 5.6.3, and 2017.3.1 to improve compatibility with the range of these versions of Unity
Support website (http://www.dlnkworks.com/support/)
Publisher website (http://www.dlnkworks.com/asset-store/)