Caves have played an important role in the history of Judaism and Christianity. David hid in a cave while fleeing from King Saul, the Dead Sea Scrolls were found in caves and Christians have met in caves to worship.
In the Bulgarian town of Mihalich there is a cave where a church met. Historians and archaeologists believe the cave church dates back to the 10th century.
According to A View on Cities, the St. Stephen Cave Church in Budapest was closed by Communists in 1951 and reopened in 1989. Construction of the cave church was finished in 1931.
Perhaps the best known cave church in the world is in Egypt where the Zabbaleen (the garbage collectors of Cairo) worship.
According to Wikipedia, "there are seven cave churches hidden among the caves of Mokattam Mountain. The Monastery of St. Simon the Tanner is the largest and it has an amphitheater with a seating capacity of 20,000. This church is the largest church in the Middle East."
The church honors the memory of St. Simon the Tanner, a famous Coptic Christian from the 10th century.
The cave churches have left behind a unique legacy.
In Hebrews 11 Paul writes about faithful followers of God that demonstrated amazing faith.
"They were too good for this world. They wandered over deserts and mountains, hiding in caves and holes in the ground." - Hebrews 11:38 NLT
Some Christians still meet in caves and holes to worship the God of the Universe.