#1 GO TO CHURCH - We are not talking about sudden conversions, divine calls or confessions. No, religion has nothing to do here, but Roman churches are prolific in works of art for all tastes: from Caravaggio (to Santa Maria del Popolo, for example) to Michelangelo (to Santa Maria sopra Minerva), from Borromini (go and visit San Carlino alle Quattro Fontane, you will not regret it) to Bernini (among others, Sant'Andrea al Quirinale is one of his masterpieces).
#2 HAVE A GELATO BREAK - On holiday, everyone indulges in a sin of gluttony... So why not enjoy a tasty ice cream wandering through the city (in Piazza Vittorio there is the historic Fassi ice cream parlour, open since 1880, but in all neighbourhoods you will find authentic addresses) or indulge in a "Roman Grattachecca."
#3 BEST SUNSET VIEWS? The terrace of Castel Sant'Angelo, to observe simultaneously both the domes of the churches and the bend of the Tiber river, which at that hour have an alluring colour.