"What did you discover?" The others immediately gathered around.
"Look at the cave wall, there are marks made by someone chiseling." Sun Hang said, "It looks like a cross."
Just as he said, about half a meter deep into the cave from the entrance, at a central height, there was a cross-shaped mark.
This engraving seemed to be chiseled out gradually using some kind of metal tool, with very uniform thickness, both the vertical and horizontal lines were a finger's width, about two millimeters deep, with the top and the sides of the cross being of similar length, only the bottom extending further.
"Isn't this a cross symbol?" Wang Xiyi immediately said, "The cross, and this is the thirteenth cave... this seems to have some special religious significance, doesn't it?"
Yang Lian labeled the cave entrance in order, starting from the first one, and this entrance happened to be the thirteenth.
