Meteora is one of the biggest and most important group of monasteries in Greece. In a region of almost inaccessible sandstone peaks in the Greek mainland, monks settled on these 'columns of the sky' from the 11th century onwards. The rock monasteries have been characterized by UNESCO as a unique phenomenon of cultural heritage and they form one of the most important stations of cultural map of Greece. Twenty-four of these monasteries were built, despite incredible difficulties, at the time of the great revival of the eremitic ideal in the 15th century. Some of these can be visited today, suspended in time... and space. Their 16th-century frescoes mark a key stage in the development of post-Byzantine painting.