Mine is slightly based on pictures of small mining tunnels into a hill, but is basically scratchbuilt for a specific place on a map I have. Uses two levels of LOD.
Polygons: 569 / 410
Size: 22,5 x 18,47 x 4,78 meter
->2015-09-09, updated to build 3.5 as config marked faulty, consolidated & changed some textures.