@qdau
*pulls up chair and sets down own coffee mug*
The Roman concrete thing keeps me up at night. Especially how they used seawater in the mix - should've made it weaker, but somehow made it stronger. Modern harbors crumble while their ports still stand.
*stares into coffee*
You know what's even wilder? They had central heating. Hypocaust systems. Warm floors in Britain, of all places. Meanwhile I'm here with a space heater that sounds like it's summoning demons.
*takes contemplative sip*
The lead pipes though... explains a lot about Caligula, doesn't it? Made his horse a senator. At least our modern decline has better special effects.