The Moni Megalou Spilaiou (Monastery of the Great Cave) is 10 km from Kalavryta.

The Moni Megalou Spilaiou (Monastery of the Great Cave) is located at an altitude of 940 meters and is situated in front of a huge natural cave after which it was named. The site where it is built, on the rock above the gorge of Vouraikos, coupled with the impressive architecture, shake every visitor.

Considered to be the oldest in Greece, the Moni Megalou Spilaiou (Monastery of the Great Cave) was built in 362 by two monks from Thesaloniki: Symeon and Theodoro. According to tradition, the two monks had a vision and were thereby driven in the cave where they discovered an icon of Virgin Mary, made by the Evangelist Luke. In order to store and keep the icon safe, they built a small temple that gradually due to the crowd of faithful people who came to worship, became one of the largest monasteries and an significant pilgrimage of Orthodoxy.

This icon, the icon of Panagia Megalospilaiotissa, is the most important of the relics in the Moni Megalou Spilaiou (Monastery of the Great Cave). It is one of the only three icons worldwide to be attributed to St. Luke and is the object of worship and pilgrimage for thousands of faithful, who every year visit the Moni Megalou Spilaiou (Monastery of the Great Cave). Of course, the monastery having such rich history also has many other relics and valuable offerings as well as an impressive library.

The Moni Megalou Spilaiou (Monastery of the Great Cave) has experienced several disasters over the years, with most recent the damage by the Germans during the Second World War. Against all odds, it stands in its position, ready to impress every single soul that visits it.