Rome hosted the 1960 Summer Olympics, using a combination of ancient sites such as the Villa Borghese and the Thermae of Caracalla, as well as many new structures, most notably the Olympic Stadium & the Villaggio Olimpico (Olympic Village).
The village was located north of the city center, and was created to host the athletes during the games and redeveloped as a residential district. In addition to the 2 stadiums and 1,500 residential units, the Olympic Village is a more-or-less complete community including shopping, schools, and a church. (Karabenick, 1963)
Rome made an initial bid to host the 2020 Summer Olympics but it
was withdrawn before the deadline.
Photos on this page come from Olympic.org.