Located in the Psirri district of Athens, this small, well-hidden Greek orthodox church is dedicated to St. John the Baptist. It is a small, single-aisle chapel originally built in the 12th century on the foundations of an older church dating back to the 9th century.

There are many Byzantine-era churches still standing in Athens, but what makes this one unique—and gives it its nickname, Agios Ioannis stin Kolona (St John around the Column)—is that it was built around an ancient Corinthian column dating back to the 5th century BC. It’s believed the column was part of a sanctuary dedicated to Asclepios, the Greek god of medicine and healing, as many as 2,500 years ago.

In 1917, during excavations west of the church, a mosaic floor and sculpture dating to the 5th century were unearthed. Additional excavations exposed six ancient wells. Stranger still, underneath the church’s foundation flows the ancient river of Eridanos. On the day after a heavy rain you can hear water moving beneath the church.

The walls of the church are covered with numerous icons, St. John the Baptist being, of course, the predominant one. The church currently operates as a chapel for the nearby church of Saint Dimitri and has liturgy once a month and special occasions. It also commemorates the martyring by beheading of St. John the Baptist annually on August 29th.