The largest of the 21 fortresses of the Metaxa line, the Roupel or Rupel Fort (also called Metaxa Fortress) sits 322 meters above sea level and overlooks the Roupel Pass between mounts Bellas and Aggistro. It was surrendered to the Germans on April 10, 1941, after a historic 4-day battle. Splendid views from what is now a museum and monument. Tours are provided of the large complex of mostly underground bunkers. It comprises 6.1 out of the 155 kilometres of the full line of fortifications.