This stone gate is more like a little alcove. It is simple yet nice and there is a shrine where people pray. There’s also a sort of open-air chapel inside where people worship. I’m Christian, but not Catholic so I haven’t prayed or worshipped there but it has a very reverent and peaceful presence.
There is a “thank you” wall where people have expressed their thanks and feelings on stones or plaques placed in/on the wall which are nice to read. I’ve walked through it on both of my trips to Croatia and have enjoyed it each time.
I’ll add photos soon.