Although many of the world's most impressive churches feature high ceilings and soaring spires, sometimes you have to go underground to find the real gems. The Huffington Post has published a gallery of the most astonishing.
Jesus called the apostle Peter, the rock on which "I will build my church," but these churches are built inside the rock or carved into it.
Cave churches and monasteries have been around since the beginning of the church, often as a way to seek out spiritual succour in a remote and solitary place. Carved into the rock, or located inside caves, they have a raw appeal that often contrasts with urban cathedrals with stained glass windows.
Photo: Church in Cairo
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