The Ghost Under the bridge

The Natisone River divides Cividale (pronounced Chivvydarly) with a huge canyon. The original wooden structure is now replaced with an impressive stone bridge that provides significant views of the river and town.
We found a hidden, locked door and borrowed the key from the nearby bar. We descended stone steps into grotto like rooms deep below the bridge. Scholars are divided on what these rooms actually were used for…… Roman gaol, Jewish bathhouse or Celtic funeral area?
When we looked at our photos, we saw either a mask sculptured into the wall or was it the ghost of Devil’s Bridge?