OK

While Rome ruled the world, Jesus Christ, son of Mary, was born in a cave, not in a wooden stable. Caves were used to house animals because they retained heat. A large church is now built over the cave, and people can go inside. The carpenters of Jesus’ day were really stonecutters as wood was not used as widely as it is today. So whenever you see a Christmas nativity scene with a wooden stable, that’s the "American" version, not the Biblical one.

A cave, I think.