This monastery is the largest and oldest of the Eastern Orthodox monasteries perched atop the rock pillars of Meteora. It's official Name is Holy Monastery of the Transfiguration of the Saviour (commonly called Great Meteoron or Megalo Meteoro). It was built on a massive sandstone rock known as Platys Lithos (Broad Rock), rising over 415 meters (1,362 feet) above the Piniós valley floor near Kalabaka and Kastraki. It was founded around 1340 by Saint Athanasios the Meteorite, a scholar monk from Mount Athos.

It is approximately 300 steps up to the top where people enter. You can see part of the line crawling up the hill to the entrance. Note that you have to go down quite a way from the side I'm photographing this from before you get to the bottom step to go back up the other side.