On top of the world

Welcome to the Roussanou Monastery, nestled amidst the towering cliffs of the Meteora rock formation in Thessaly, northern Greece. Roussanou is one of the six monasteries that remain active in this UNESCO World Heritage Site. Despite the construction difficulties, 24 monasteries were founded on these 'columns of the sky' in the 14th and 15th centuries.
© Marius Roman/Getty Images