The abandoned sulphur mine in the bay of Paliorema on the east coast of Milos provides the destination for a little hike. As an alternative, you can drive almost down to the beach in an off-road vehicle. Signs with the word “Thiorichía”, which is Greek for “sulphur mines,” show the way.
Decades ago, sulphur was mined, processed and shipped in the steep, deep-cut valley. Although the entire installation with its buildings, machines and loading gear has been heavily eroded by the ravages of time, astoundingly it still sits undisturbed in the landscape as a ghostly industrial ruin. At the far end of the valley there are numerous galleries that were dug into the hillsides.
For reasons of safety the mine and galleries can no longer be entered.
Source:
http://milos-greece.com/en/sulphur-mine.html