In the 1960s, locals discovered a secret passageway in one of the oldest churches in Malta. Within, they found a wooden shoe sole, a small wooden cross, three coins, pieces of pottery, chainmail armour, and a large pile of human bones.

St. Catherine’s Old Church sits on the outskirts of Żejtun. It’s dedicated to St. Catherine of the Wheel, but locals call it Saint Gregory’s for a traditional procession held yearly on the first Wednesday after Easter Sunday.

Very little remains of the original medieval church, built before 1436. The church’s present edifice is a fusion of Gothic and Romanesque and dates back to the 16th century. Its dome is one of the oldest Maltese cupolas. Around the dome is a secret passage built in the walls of the southern transept. The passage is U-shaped and contains a large number of human bones.

Local legend claims that the people were buried alive within these passages during the siege of 1614. Studies conducted between 1978 and 1980 concluded that the bones were probably exhumed and moved there from a cemetery, and that the deaths had all occurred around the same time.

For about three centuries St. Gregory’s served as the parish church for all of southeast Malta. The church once doubled as a watchtower; the orientation of the southeast transept of the church is aligned with the bays of Marsaxlokk harbour, St. Thomas Bay, and Marsascala Bay. The church occupies the highest point that overlooks the harbours in the south, a once frequent landing spot for Barbary pirates. The secret tunnel was ideal for the lookouts who watched for pirates in the bays. Unwanted landings were communicated to French troops in the north via smoke signals from the roof of the church.