Pompeii and Herculaneum were destroyed in different ways in the eruption and this means they have been preserved differently. Pompeii had many hours when it rained volcanic ash and rocks. Thus, many buildings collapsed from the weight of the stones, killing some of the victims who were sheltering indoors. Even some of the victims found in the streets were killed by falling debris. Pompeii, thus, was pretty much smashed and broken before the heat of the pyroclastic flow killed everything that remained alive.
Herculaneum, on the other hand, did not have the raining rock, but was engulfed by 4 or 5 waves of pyroclastic flow to a much deeper depth than Pompeii. Anything living was killed instantly and all the organic material in the city was fried. Paradoxically, this means that much survived in the form of charcoal. But the particular characteristics of the flow that covered the city also made it much harder to excavate. The depth of the flow also meant that some of the present city of Ercolano was built right over the old city. So only about 1/4 of it is excavated.
The story I heard is that a farmer digging a well discovered Herculaneum. Might be true, but whatever happened, by the early 18th century when there was a Bourbon King of Naples, they developed a unique method for excavating the very difficult covering of the city. They tunneled through it. The goal was treasure-seeking for the Bourbons and there was little thought given to what was destroyed in the process. Nor was there any established method for excavation. There are a few places where you can still see the tunnels made by Bourbon excavators.
As we approached Herculaneum, when we were looking down on it as above, we could hear the most amazing noise. We couldn't figure out what it was until we got down to the beginning level of the city. It turned out that it was very swampy and there were zillions of frogs making noises. I took a little video so you could hear it. By the way, the arches you can see in this video were boat houses and storage areas. This was the beachfront of Herculaneum, which has only been excavated in the last few years. There had only been a couple of bodies found in Herculaneum, so they figured that people were able to be evacuated. However, here they have found over 300 skeletons clustered in these arched caverns. Also, notice how high the hill surrounding this area is - you glimpse trees on top of the hill at one point. That is volcanic material, and shows how deeply it was buried.
Herculaneum was far less crowded and had far far more intact and fascinating things to see. Plus, it was smaller so it was possible to see everything. Although, we learned here, again, that 2/3 of the site had been closed in 2000 because it was deteriorating rapidly. But there was still a lot to see.
I'll post many more pictures in the next post.