Spiders?
Or more likely could it be when the occupants die, instead of someone new moving in they torch the place and start over?
Edit: nevermind, they suggested that further down in the article.
Yeah, spiders seemed like the obvious answer to me. I would have also accepted centipedes.
Huh. I was expecting they did it to destroy contagion, but that’s not in the article
Clearly it’s insurance fraud
Lice, mites, fleas? we were gross back then.
Heh. “Were.”
[…T]hey have discovered evidence of numerous ancient civilizations on the planet, all destroyed by fire, with the collapses occurring about 2,000 years apart. […E]arlier civilizations on Lagash were destroyed by people who went insane during previous [solar] eclipses and, desperate for any light source, started large fires that destroyed cities.
– Extract from the plot summary of “Nightfall” by Isaac Asimov, https://en.wikipedia.org/wiki/Nightfall_(Asimov_novelette_and_novel)
