If you have had a chance to walk around an old European centrum, you've no doubt come across cobblestone. Or just stone, ancient streets. Stones which may have been laid hundreds of years ago. Yet here they lie. We walk, perhaps stumble. Our shoes may or may not accomodate such surfaces. But back then?
One must admit that there is a degree of charm to these surfaces. Quite utilitarian as well. To get to plumbing beneath, simply remove stone, fix, replace stone.
I have a theory.