In Kalavryta Megalo Spileo meaning “Monastery of the Big Cave”, this 8-floor centre of worship was carved into the mountain and built at a height of 924 meters. The Monastery of Mega Spileo was originally built in 362 AD by two brothers, Symeon and Theodore, when a shepherd girl found an icon of the Virgin Mary inside a cave. The icon was made of wax and mastic and it is believed that Apostle Luke painted it.
The Monastery was actually destroyed five times since its inception, the most recent being by the Nazis in 1943.
Today in spite of all these damages, the Monastery of Mega Spileo is an imposing construction with a 17th century church that hosts remarkable frescoes, mosaic floors and a bronze door with relief decoration. The Monastery also hosts a museum that displays carved wooden crosses, antique manuscripts and Holy Gospels. A good number of its important relics are also kept in a special hall. The Monastery of Megalo  Spileo celebrates every year on August 15th, on the name day of the Virgin Mary, who is the saint protector of the monastery.