Open top bus tour

Final day in Rome. I had to check out of my Airbnb by 10 AM but my flight isn't till 7pm. I needed to therefore waste some time and I didn't fancy walking around in the heat with big bags. After scouting out where my airport bus went from, it was conveniently next to the tourist tour buses. I was happy enough to purchase a tour round the city. Although I could hop on and off, I just sat on board for a full loop. It confirmed I had been to all the main sights (that are visible from a big road) and I got a commentary along the way.