La Rotunda is located in one of the best parts of Roma up in Aventino very near to the 13th Century church Sant Sabina. Being up on the 6th floor looking at the Umbrella pine trees (Pinus pinea) and the birds from the balconies is a great place for the aperitivo. Great ristorantes and cafes in nearby Testachio - (eg Antica Forno; Volpetti - 5 minutes walk).
And hosts Martha and Patrick are most accommodating.
Highly recommended.