The next one in a series of a test of skills, hope you like it.
The modifiers on both grounds (above the entrance and below) are turned off to avoid slow file startup, just turn them back on in the modifiers tab by clicking on the eye icon for each object.
Due to huge increase in file size, the .blend is unpacked of course.
Rendered in Cycles at 10.000 Samples.
strange...but realy cool ! :)