Panagia Ekatontapyliani is the gem of Paros, also known as the Church of 100 Doors, it is a historic Byzantine church complex and an ancient temple of Artemis located in the town of Paroikia. This complex contains a main temple surrounded by two smaller ones as well a baptistery on the east side.
The church dates back to 326 AD. Its oldest features likely predate the adoption of Christianity as well as the state religion of the Roman Empire in 391 AD. The church was allegedly founded by the mother of the Roman Emperor Constantine the Great (ruled 306–337 AD), Saint Helen, during her pilgrimage to the Holy Land when she stopped to worship at a chapel on the island.