Humans are usually disgusted by decay. Evolution has taught us to turn up our noses at sunken pears and moldy biscuits. But when it comes to architecture, we can’t get enough of it. People love ruins.

It’s an old love. The cultures most commonly associated with ruins—the Greeks and Romans—were fascinated by the broken remains of still more ancient civilizations. When, in turn, celebration of the Greeks and Romans reached a zenith in the 18th and 19th centuries, the fad became so intense that no European country estate was complete without an imitation ruin—manicured ivy on freshly laid plaster.

Large timescales are hard to fathom, and ruins give the mind a sense of history that few other things can. Add to that the strange, intoxicating feeling of being alive in the imagined p...