Pompeii was one of the most important commercial centers in the Campania with a population estimated at 20.000, of which 10% died by intoxication or suffocation during the outbreak. Because the whole town was frozen in time it gives a very detailed image of life in the first century of the imperial Roman Empire. Not only that, it also gives an image of the people living there. An impressive, if somewhat grisly, site in Pompeii is a small museum where they keep the casts of dead citizens. These people were killed by the gases erupting from the volcano and then buried by the ashes. These ashes then hardened, and left a perfect mold of the bodies, which in time decomposed. These were filled with plaster by modern day archaeologists and give us a chilling insight in the enormous tragedy that took place.
Now the streets that had been deserted and forgotten under a thick layer of ashes are once again lively, but now with tourists attracted to this unique site. Walking through the streets, you can find evidence of the people who lived there everywhere. Not only (obviously) in the buildings, but especially in the painted signs outside the shops and, most charming perhaps, the graffiti on the walls. The Pompeians were enthusiastic wall-scribblers, and (provided you know a little Latin) you can find all sorts of statements, ranging from random wisdom (Profit is happiness), to declarations of love to petty insults (Oppius, clown, thief, petty crook!).
When visiting, make sure you dont miss the House of the Tragic Poet, the House of the Vetii and the Amphitheater. The last one gives an excellent view over the site. Also dont miss the Villa dei Mystery, especially not if youve read Donna Tarts Secret History.