Herculaneum: Priority Entrance

If big-budget sword-and-sandal flick Pompeii got you hot and flustered, prepare for Herculaneum - an ancient Roman town that has, most unfairly, been overshadowed by Pompeii's fame. Herculaneum is, in fact, more interesting, better preserved and far easier to navigate. See clothing, mosaics, and frescoes in their near-perfect Roman glory and imagine life before Vesuvius's eruption in 79 AD.
When Vesuvius erupted, Pompeii was quickly buried in ash. Herculaneum ( Ercolano in Italian), being upwind, was destroyed over 12 hours later when a 400° C blast of searing ash, pumice, rock and volcanic gas struck at over 100 km/h, essentially pausing the town in that moment.
See the old arena, as big as a city block, and The Palestra (Main Hall) which was home to a giant statue of Hercules, hence the town's name. If you explore with an audio guide (€8) you'll get a great sense of the history.
A modern-day visit to Herculaneum puts you in the shadows of Mount Vesuvius, in a town that was wealthier than Pompeii and better preserved. And that wealth is on full display here: in the marble of the bathhouses, in the furniture, even in the items of clothing that were all kept intact, thanks to the volcanic ash and debris which coated it all, acting like a magic time-freezer.