Discovered accidentally in 1934 during quarrying, the Crypt of Agia Philothei is a small natural cave, converted into a chapel by Rigoula Venizelou. The daughter of a famous 16th-century family that lived in Athens during Ottoman occupation, Venizelou died a martyr, and was later canonised with the name Agia Philothei.
After the crypt’s discovery, the village of Nea Alexandria was officially renamed Philothei in her honour.
The crypt, via underground tunnel, connects to the Kalogreza Convent, established by the saint herself on one of her family estates. The Church of Agia Philothei is located beside the crypt.