Herculaneum is a Roman town that was destroyed in the 79 AD eruption of Vesuvius. It's become less famous than nearby Pompeii but it is better preserved in many ways. When Vesuvius erupted in mid-afternoon, the prevailing winds carried the ash over Pompeii burying and destroying it. Herculaneum was not seriously affected at the time. Later that night however when much of the town had been evacuated, pyroclastic flows buried everything including about 300 people waiting in the boat houses for evacuation. The boat houses are the arches in the foreground here. What now appears to be a moat was the oceanfront before Vesuvius erupted.
The intense heat from pyroclastic flow preserved Herculaneum in different ways than what happened in Pompeii. The streets are intact much as they are in Pompeii but the buildings are far better preserved as they were buried instantly without collapsing first under the weight of the ash.
Herculaneum at the time of the eruption was a small seaport and was more affluent than Pompeii. Several of the oceanfront villas here were quite lavish.
This garden for instance would've looked out onto the Tyrrhenian Sea before the eruption. Now it looks into a cross section of earth from six separate pyroclastic flows and almost 2000 years of sediment.
The interior of the homes here are far better preserved than those at Pompeii.
The central mosaics are reproductions here (the originals have been moved to Naples) but the originals on either side of them can clearly be seen.
The painting and mosaics on many of the walls and floors of the homes are surprisingly well preserved. Both can be seen in this room.
Public baths at Herculaneum have also survived fairly well. The individual shelves and hooks for clothing still line the walls. The earthquake that preceded the eruption caused some damage to the floors but this mosaic in the baths is almost completely unscathed.
The site of Herculaneum is small compared to Pompeii. It can be seen in just a few hours. The public (once seafront) square in the bottom of this picture is one end of the city, the brown wall near the top is the far side. The city was laid out in a grid pattern much like Pompeii. Behind the archeological site is the modern city of Ercolano, still located in the narrow strip of land between Vesuvius and the sea.