The Romans were serious about concrete. Using a naturally occurring cement from volcanic ash deposits at Puteoli, near Pompeii and Mount Vesuvius, they built their aqueducts and their bathhouses. Walk into the Pantheon in Rome, a building that will soon celebrate its 1,900th birthday. Gaze up at what was, for centuries, the largest dome on the planet.5 You’re looking at concrete. It’s shockingly modern.
