Meteora

The rock pillars of Meteora ("suspended in the air") rise up to 400 metres above the Thessalian plain, formed around 60 million years ago as a river delta whose sediments were later uplifted and eroded into the smooth, sheer columns visible today. Hermit monks began occupying caves and fissures in the rock from at least the 9th century CE, but the construction of monasteries on the summits themselves began in the 14th century, reportedly motivated by a desire for protection from Turkish raids during the decline of the Byzantine Empire — the inaccessibility of the rock pillars made them effectively impregnable.

At their height, the complex included 24 monasteries; six remain active today. Until the early 20th century, access to most of the monasteries was by retractable wooden ladders that could be pulled up in the event of danger, or by nets and baskets winched up by ropes — a method of access so precarious that, according to a popular (though likely apocryphal) saying among visiting monks, the rope was replaced "when the Lord let it break." Steps cut into the rock were added in the 1920s, dramatically easing access, and the monasteries were used as hiding places for Greek resistance fighters during the Second World War, during which several were damaged by bombing. Meteora was inscribed as a UNESCO World Heritage Site in 1988 for both its natural and cultural significance.