Meteora

Meteora, in the Thessaly region of central Greece, is a cluster of towering sandstone and conglomerate pillars rising as much as 400 meters above the surrounding plain, formed from a thick sedimentary deposit laid down by a river delta some 60 million years ago and later thrust upward and exposed by the tectonic collision that raised the Pindus mountain range. As the sedimentary rock was uplifted and fractured by this tectonic activity, natural vertical joints and fissures developed through the mass; subsequent weathering by wind, water and extreme temperature variation over millions of years widened these fractures and eroded away the intervening rock, leaving the isolated pillars standing separately across the plain. Their remote, near-inaccessible summits led Orthodox monks beginning in the fourteenth century to build monasteries directly atop several of the pillars, and Meteora is inscribed as a UNESCO World Heritage Site for both its unusual geology and its religious architecture.