Sometimes catastrophic disasters are the best for preserving a site for posterity — the ash-covered Roman city of Pompeii is perhaps the most famous example of that. Pompeii is massive and one of the best-preserved Roman cities in the world and is remarkably frozen in time. The site is ginormous, and it takes the better part of a day of exploring to see it. Most archeological sites only preserve parts of a citadel, but here much of the city is on display.

But Pompeii is arguably not even the best-preserved Roman city. A short distance from Pompeii is the remarkable Roman town of Herculaneum which met the same fate during the eruption of Vesuvius. The eruption of Vesuvius in AD 79 also buried the town of Herculaneum under a massive sheet of volcanic ash and pumice.