Santorini is one of the great natural wonders of the world, and its main attraction is the landscape and seascape of the island itself. The configuration of the present, roughly semicircular island is the result of an enormous volcanic explosion which occurred probably around 1630 bce, literally blowing the top off the island and changing what had been a typical half-submerged mountain of an Aegean island into a flooded crescent caldera, in the middle of which a few small smoking islands still bear witness to volcanic activity. Some have speculated that this event was the inspiration for the myth of Atlantis. Tours to the central "smoking" islands are readily available and one can see and feel steam vents and recent (1950s) lava flows. Another popular reason for coming to Santorini are the legendary sunsets, some of the most spectacular in the world. Ia is one of the few places on the island which is both close to a sea and offers a good view to a sunset over the sea: in other towns, the sun disappears behind the volcano.