How the rocks of Meteora were born

Stand at the foot of Meteora, in Kastraki or on the edge of Kalambaka, and look closely at the rock. What seems from a distance to be solid grey stone is packed with rounded cobbles, like pebbles from a riverbed. That is exactly what they are: material carried by rivers into a sea that no longer exists.

A sea between mountains

This was once the Mesohellenic Trough. According to the Meteora-Pyli Geopark, it was a huge sea basin running from present-day Thessaly all the way to present-day Albania, at least 200 kilometres long and 30 to 40 kilometres wide. The Pindos range rose to the west, with mountains such as Vermio and Vourinos to the east.

For millions of years, large rivers wore those mountains down and carried gravel, cobbles and sand into the sea. Deltas built up at their mouths, and the material settled underwater, layer upon layer. This is how the Meteora Conglomerates came to be: cohesive conglomerates with beds of sandstone, part of the Pentalofos-Meteora Formation. The Geopark gives them an age of 10 to 30 million years, in the Oligocene and Miocene.

From seabed to pillars

Today that old seabed stands on end, in rocks up to 200 metres high spread over more than 7 square kilometres, the Geopark says. Movements of the Earth’s crust broke the conglomerates with faults and fractures. Water ran through the cracks, winter ice forced them wider and the wind did the rest, until steep ravines opened up and split the mass into separate rocks.

As shapes, the pillars are far younger than the stone they are made of. A 2020 study in the scientific journal Geoheritage places the start of the erosion that carved them in the Pleistocene, around 700,000 years ago, although the authors themselves describe that estimate as very rough.

Meteora has been a UNESCO World Heritage Site since 1988, listed as a mixed site for both its natural and its cultural value. Since 2024 the area has also been part of the UNESCO Global Geoparks, as the Meteora-Pyli Geopark.

Reading the rock up close

Walk up to the base of a rock and you will see cobbles of every size and colour, locked into the stone. According to the Geopark, they are fragments of metamorphic, granitic and carbonate rocks from the mountains around the Trough, brought here by the rivers.

Then take a step back. The horizontal bands across the rock faces are the layers of the old delta, conglomerate and sandstone in turn. Where the softer layers wear away faster, hollows called tafoni open up; the Geopark notes that they mostly follow the bedding, which is why they line up in horizontal rows.

Good to know

• Tafoni are easy to spot at the western exit of Kalambaka towards Kastraki, on the rocks known as Amparia and Bandova.
• Look mainly at the south-facing sides: that is where tafoni develop most, because of the sun and the weather.
• South of Kastraki stands Adrachti, a lone pillar left over from a larger rock, already shown in 18th-century copper engravings.
• Layers and cobbles stand out best in low, raking light, early in the morning or late in the afternoon.
• Leave the cobbles where they are: they are part of a World Heritage Site.