I.M.M LAVRA or Great Lavra or Megistas Lavra
The oldest monastery on Agion Oros ( Mount Athos) is located on the south East tip of the peninsula.
It was founded in 963 by St Athanasios the Athonite.
It has the highest ranking of the 20 monasteries on Mount Athos.
For more information on how to get to Mount Athos please check my other geocache GC1BMZY for more explanation.
Good luck and let the Lord be with you.