Thanks for clarifying your position. I agree that we could build 2,000 year structures when we intend to. I wouldn't be surprised if some of our nation-scale w

Thanks for clarifying your position. I agree that we could build 2,000 year structures when we intend to. I wouldn't be surprised if some of our nation-scale works like the Hoover Dam last that long. The Long Now foundation is even trying to build something that lasts for 10,000 years. But I disagree that there's no secret to be discovered in Roman concrete. Materials science involves a lot of guess-and-test work and luck, and there's no harm in exploring whether the ancients might have had better luck with some of their guesses.