It is hard to imagine them building this. It must have taken enormous effort to carve this into the ground. It is a unique structure. Having said that, we did not think it was worth the cost of the visit when you can enter magnificent cathedrals for the same price. If you have time to kill, I would visit but there are better things to do.
If you own or manage Pozzo di San Patrizio (St. Patrick's Well), register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.