Re: ancient construction techniques rediscovered-hydraulic lime

While in Greece I laid my eyeball down on the upper foundation edge of an old island ruin. I couldn't see any deviation up down or in out down a 100 foot run. Everything is solid rock underground so I'm sure that helps keep it that way but having been perfect from the beginning is more than just amazing.

The pyramids I think were protected by a several foot thick layer of limestone. It's that part you see eaten away in photos of them that looks almost like a crust.