Subterranea_(geography)
Subterranea are underground structures, both natural (such as caves) and human-made (such as mines).[1]
Some subterranea and related topics include:
Share this article:
This article uses material from the Wikipedia article Subterranea_(geography), and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.