Rome, such a magical destination for so many reasons. But the eternal city is known to get oppressively hot this time of year. You may want to take a short trip out to Tivoli Villa d'Este. It’s higher than the city, so it's cooler, and filled with an astonishing array of fountains. We have been told that this was the model for what has come to be known as the Italian style of a formal garden. Feel the power. It’s amazing.
Just down the road is Hadrian’s villa, a bit of a wreck, but worth the visit, especially with an informed guide. The whole trip can be done in half a day, in time to get you back to town for that evening drink in Trastevere. We used Gray Line tours, $80 all in.