When most people think of a Greek island, their mind wanders to the blue and white homes on the Santorini hillside, or the party paradise Mykonos. There are of course hundreds of other island destinations throughout Greece, but the Cyclades have become a symbol of an idyllic Greek summer getaway. These islands have a scorching hot history and story, millions of years in the making.

To understand the origins of the Cyclades island chain, we must delve deep into the Earth. The geologic processes that shaped the Mediterranean region and all of the continents as we know them are incredibly intricate. A major component is the spread of hot magma below the Earth’s crust, and sometimes above the surface in the form of lava from volcanos. The layer of the Earth just below the crust is called the mantle. In the deepest parts of the mantle there is extreme heat and in other parts there is volatile movement of materials. The processes that occur in the deep mantle also affect what is happening in the upper regions of the mantle called the asthenosphere and the lithosphere. The mantle is important in the Earth’s evolution and current geologic processes because it comprises 84% of the planet’s volume. Over the course of 4.5 billion years of moving and shaping itself, water, gases, and minerals became trapped in the Earth’s mantle. These materials are pushing their way to the surface and erupt through or alter the crust through different geologic processes. These processes include the movement of tectonic plates, which then shapes the landscape, for example forming new mountains or ocean crust layers. There are other processes like volcanic eruptions, where these materials are expelled from the mantle through the crust in the form of hot melted rock and minerals turned into lava.

Volcanoes can be found throughout the Mediterranean from Italy to Africa to Greece. The Cyclades islands are in a region known as the Aegean Volcanic Arc. This region is known to have an active tectonic plate boundary in which two plates in the Earth’s mantle are constantly causing friction between them. The African plate is being pushed under the Eurasian plate and this initiates a process called subduction. Subduction is when the contents of one tectonic plate are forced under another tectonic plate, which then creates a subduction zone within the upper mantle of the Earth. A subduction zone in the mantle causes the materials that have been pushed down to be heated through a strong force of friction. These materials, including rocks, minerals, and water then shoot up all the way through the crust to the surface in the form of volcanic eruptions.

This is how many of the islands in the Mediterranean were formed, including the Cyclades island chain. The Aegean Sea was also flooded and formed as a result of shifting plate tectonics and breaks in the Earth’s crust.

The most famous volcano in the Cyclades is certainly the one that created the island Santorini. Today, the island is in the form a C-shape, with the caldera of the volcano located in the middle with a tiny island of its own named Nea Kameni with other smaller formations surrounding it. The significance of the Santorini volcano can be traced back to antiquity and the infamous civilizations it erased when it erupted. The Minoans were a highly civilized and far-reaching group with settlements throughout the Aegean. When the Santorini volcano erupted around 1600 BC, the major settlement on the island called Akrotiri was completely destroyed. Scientists believe the inhabitants had prior warning signs to evacuate since no human remains were found at the archeological site, now a museum of the ancient city. Some have called Akrotiri the true lost city of Atlantis, because when the volcano erupted it also triggered massive tsunamis. The forces of the eruption and the subsequent tsunamis also affected settlements as far as the island of Crete in the southern Aegean, over 100 kilometers away. Through scientific measurements and research, the eruption was a categorized as a 7 VEI and is believed to be one of the most catastrophic in human history. The effects of this event were mentioned in the records of ancient civilizations throughout the Mediterranean and beyond, including those in Egypt and even China. This is because the aftermath of the huge eruption left lingering particles and dust in the atmosphere, which then traveled and affected the global climate. The Santorini volcano is still active today and its last recorded eruption occurred in 1950, with warning signs in the form of earthquakes.

The aftermath of such volcanic activity leaves traces by layering the landscape in volcanic ash. The cliffsides of the Cyclades islands display layers of sediment with their various colors and properties. Black, red, and white sand beaches are exotic detours from the normal tourist spots.

The active Aegean Volcanic Arc stretches from the southern side of the Corinthos Canal to the Cyclades islands and to the southwestern edge of Turkey. Other Cyclades islands that fall within this fiery region include Milos, Ios, Astypalea, and Nisyros among others. Their rocky and often white or dark colored beaches and sediment contrast with islands elsewhere in the Aegean Sea and the Mediterranean overall. These islands were formed through volcanic activity resulting from subduction and many have had eruptions throughout their millions of years of existing. Milos for example, has a dormant volcano that has not erupted for almost 100,000 years. Although some eruptions were more legendary than others, the characteristics of the Cyclades islands are bound to continue evolving through these geologic processes. Volcanoes are scattered throughout the Mediterranean Sea, like Mount Etna in Sicily Italy, which is one of the largest in the world.

Perhaps it is this fiery energy that makes the sheltered Cyclades such an exciting destination. They are tucked away in a secluded part of the Mediterranean region, but carry an immense and important past and future. In the past, the Cyclades have housed impressive civilizations, in the present they gift the world some of the most stunning landscapes and natural wonders. They are a mix of the power of mother nature and also the will of humans to build their lives with beauty and culture.