Mount Vesuvius erupted and Pompeii was covered beneath the burning ashes for a long period of time. It was a major piece of rediscovery work for archaeologists to decode lives before the city was swept under rocks and lavas.
The 2-hour guided tour might give a little inside story of the historical background. The great theatre of battles for beasts and gladiators isn’t too far apart from my imagination. Nevertheless, having modern bathhouse and red light district during that era was quite a surprise; I guess everybody has their needs.
Personally, I didn’t relate well with Pompeii because roman history is just not my cup of tea. 4 hours is more than enough for Pompeii, unless you’re keen to find more about the story behind each and every chamber. And yes, Mt Vesuvius is still an active volcano!