Santorini is one of Greece’s four volcanic islands; the most famous one, actually (if you didn’t know that, check out these other interesting facts about Greece). At the center of its caldera are two small volcanic islands still active — you can even find some hot springs there.  3,600 years ago, a cataclysmic event known as the Minoan Eruption devastated the island of what was then called Thera (modern-day Santorini). It was so large and intense that earthquakes and tsunamis affected the entire region around it, changing the geography of the area forever.  It also added layers of black pumice, ash, and lava to what remained of the original island, creating the iconic black sand beaches that Santorini is now famous for. Some of the beaches are more solidly black, while others have a darker hue of brown or grey with a lower level of volcanic debris.  The strange colors of these sands also turn the waters an incredible shade — somewhere between royal blue and emerald green. It makes for a beach getaway you won’t easily forget.