Santorini used to be a round island, and for that reason the first name was Stroggyli. During an earthquake and volcano-outbreak in the 15th century BC the middle of the island sunk and gave it the shape it has today.
This is one of the reasons why many believe Santorini really is where Atlantis once was. Being a volcanic island, the beaches are not of the ubiquitous golden sand variety that you can expect to find on many Greek islands.

The south-eastern side of the island gives the best beaches of wide black lava sand. Other beaches around the island consist of black sand strewn with pumice stones and black pebbles. Kamari, Perivolos and Perissa are popular beaches on this southeast coast all with beautiful mountain surroundings and wide stretches of black sand. Generally all beaches are well organized, with sunbeds and umbrellas. Many restaurants, coffee shops and beach bars are available if you wish to have a lunch, a light cocktail or a dinner by the sea.
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Fira the capital of Santorini is built on the edge of the caldera at the west side of the island, at an altitude of 250 meters and was founded in the late 18th century. At Oia you get the best sunsets, and both Oia and Fira are excellent towns for just strolling around and shopping.
Imerovigli It is located about 2 miles north of Fira and south of Oia.

Akrotiri is an ancient town that was buried when the volcano erupted 3500 years ago. Archaeologists are still excavating it, but you can walk around in the little street quarters and see the buildings almost like they were back then.

In Pyrgos a few kilometres from the capital you can see the medieval fortress Kasteli and admire a 10th century church and a monastery both with beautiful Byzantine icons and relics. The village of Messaria is also located close to Fira (about 3,5 km) and is surrounded by vineyards, you should visit the two small churches that are built in caves.

Ancient Thira is situated on top of high cliff just above Kamari, and there is also an old church there from 1100.

a Greek island unlike any other

Santorini is perhaps the most fascinating and most talked about island of Greece in the Aegean. Only the name of the island is enough to unfold in mind pleasurable connotations, volcanic landscape, gray and red beaches, dazzling white houses, terraces with panoramic sea views , stunning sunsets, wild fun. All this, together with remnants of lost civilizations discovered in the volcanic ash justify the epithets with which visitors identify Santorini and fairly is called, magical, indescribable, astonishing.

Approaching the island by boat the immediate impression obtained is this is a Greek island unlike any other.
Today, Santorini is the only inhabited Caldera (volcano cauldron) in the world. The sunsets at Santorini, viewed from the Caldera, really are breathtakingly beautiful when seen as a backdrop to the volcano.