Interesting topic and photos. I feel the draw is the mystery and our interest in exploring the mysterious, perhaps to overcome fear of the unknown, to know what lies just beyond, to wonder why it is now as it is, abandoned of all life and falling or fallen to ruin. At the same time such places serve as momento mori, knowing we too in short time will become just as skeletal and find ourselves in an environment just as devoid of life.
And as barracuda mentioned, one also looks forward, imagining what will in time be, when all existing life and structures have turned to dust.
Oftentimes while looking back in wonder of what once was I find myself wondering about what marvels will be. And I'm sorry to report what I see for the future looks much like many of the photos.
I'm sure the jellyfish archaeologists of the future will wonder what kind of creature would create a clown-god, to which another will remind him, 'the kind that destroys its own. Maybe they took the sacrifices this wretched god demanded a bit too far. Who knows? I think the real clue to our understanding more lies in the wavy mirrors in the antechamber.'