re: #569 Backwoods_Sleuth
From what I can tell from the hotel’s website, it’s whitewashed rock.
Thera (Santorini) is composed entirely of volcanic tuff. The giant caldera in the middle is from the gigantic explosion in ~1650 B.C. that devastated nearby Crete and made the Minoan civilization vulnerable to conquest by the Mycenaean Greeks. Thera was quite possibly the Minoan metropolis at any rate, Crete just the breadbasket where the rural palaces were located.