JK, this is actually a fairly profound subject and I'm pleased to see it brought up.
Rome of course springs immediately to my mind, but not the buildings you'd think. Rather than the Colosseum, etc., I'm more attracted to the ruin of Trajan's Market, which (with the marble veneer off it) showcases a lot of the internal brick-faced concrete engineering typical of the Romans. Same goes for Nero's Domus Aurea with its little octagonal dome.
I think these ruins are beautiful because they visually expose even more "form follows function" reasoning than the buildings would if complete and intact. That's also why some of these building cross-section drawings you see are really interesting art objects in their own right.
I guess the process of weathering and breakdown actually kind of "distills" what's on the ground, highlighting what's most survivable, natural, and important.
From a golf architecture standpoint I think this holds true also. Somebody the other day was talking about hunting for remnants of GCA features on the modern land of Mill Road Farm. Sounded like an exciting hunt. And how about the old pictures of the Culver Academy nine, showing the remnant bunkers and green sites with no sand. Those pics let the imagination run wild.