We've been to Pompeii before, the last time we stayed in this part of Italy (over a decade ago, in the days when there were travel agencies). We wanted to go under our own steam, though, so we could visit the parts that tours don't go, in particular the amphitheatre. We also went to the small and large theatres (aside: an amphitheatre is an oval or a circle; a theatre is a semi-circle).
At the theatres, I was pleased to deminstrate how the acoustics worked by standing at the focal point of the semi-circle and speaking so I could hear myvoice echoed back.
We did it in both the theatres, and were somewhat surprised to find that no-one else was doing it or was even aware it could be done. We grabbed a random passer-by at one point and made him try it out. It's really effective.
We couldn't get it to work in the amphitheatre, though, perhaps because there were five workers with strimmers in there...