Two Greek Orthodox rock Monasteries in Meteora. The Holy Monastery of Great Meteoron (on the right - erected in the mid-14th century) The building serves as the main museum for tourists. The Holy Monastery of Varlaam (left). This is the second largest monastery in the Meteora complex. It was built in 1541 and embellished in 1548. The old refectory is used as a museum. They are among the 6 out of the original 24 monasteries that are still active and open to visitors. They are included in the UNESCO list of World Heritage Sites. Meteora Rock Monasteries. The Meteora (meaning in Greek "middle of the sky", "suspended in the air" or "in the heavens above") is one of the largest and most important complexes of Greek Orthodox monasteries in Greece, second only to Mount Athos. The monasteries are built on natural sandstone rock pillars, at the northwestern edge of the Plain of Thessaly near Pineios river and Pindus Mountains, in central Greece. The nearest town is Kalambaka. Some rock towers reach 550m above the plain. This great height, combined with the sheerness of the cliff walls, kept away all but the most determined visitors. Access to the monasteries was originally (and deliberately) difficult, requiring either long ladders lashed together or large nets used to haul up both goods and people. Until the 17th century, the primary means of conveying goods and people to the rock monasteries was by means of baskets and ropes. Six of the 24 monasteries remain active today. Each monastery has fewer than 10 inhabitants. The monasteries are now tourist attractions. Meteora, Kalambaka, Thessaly Region, Greece, Mediterranean, February 2015.