Santorini

Approaching Santorini by sea, the scale of the place becomes clear before a single foot touches the ground. The island is horseshoe-shaped, its steep cliffs carved from layered volcanic rock, and at its heart lies a flooded crater — a caldera roughly 12 kilometres across and more than 400 metres deep in places. This is the shell of one of the largest volcanic eruptions in recorded human history, and the sea has slowly filled the void it left behind.

The caldera rim

The rim of the caldera forms a near-continuous arc above the water. In places the cliffs drop almost vertically — bands of dark basalt, red volcanic tuff and pale pumice stacked in strata that record thousands of years of eruptions in stone. From the path between Fira and Oia, the views across the caldera are wide and uninterrupted: blue water in every direction, the silhouette of the opposite rim, and the small volcanic islet of Nea Kameni rising dark from the centre of the crater. The light here changes through the day, flattening or sharpening the caldera walls depending on the angle and the season.

Nea Kameni and the volcanic islands

The youngest land in the area is Nea Kameni, an island of bare grey lava formed from a series of eruptions between the 17th and 20th centuries. Walking across its solidified lava flows, it is possible to see the craters and small steaming vents that remain active below the surface. The rocks hold heat from below, and in places the ground is warm underfoot. Pale sulphur deposits colour patches of rock in yellow and green. Swimming near the island, the water is noticeably warmer than it would be at this latitude — a consequence of submarine vents on the caldera floor. Volcanic sand beaches on Santorini's southern and eastern shores tend toward dark reds and blacks rather than the pale sand common elsewhere, a direct product of the island's volcanic geology.

Soil and cultivation

The volcanic origins of the island are not only visible in its dramatic landforms but present in the soil beneath the vineyards and kitchen gardens that occupy its flatter areas. The mineral-rich, free-draining earth is one reason Santorini's Assyrtiko grape variety has developed its particular character, producing wines with a mineral backbone that reflect their origin. The island's settlements — villages of whitewashed cubic houses and churches with dome roofs — sit on the upper edge of the caldera rim, their light-coloured surfaces historically chosen for their ability to reflect heat. Together, the geology of the cliffs, the sea in the crater, the dark beaches and the volcanic soil form a landscape whose character is inseparable from its volcanic past.