<human>:  How can I plan a 3-day vacation itinerary in Rome, Italy?
<bot>: Day 1: Begin with a tour of the Colosseum and take a guided visit of the Vatican City and museums. After that, end your day with an evening stroll around the Trevi Fountain and Spanish Steps. Day 2: Start the day with a visit to the Pantheon, after which head to explore the city’s many covered markets like Campo de’Fiori. Wander around Trastevere and take a break for some delicious Italian pizza and gelato.Day 3: Take in the Ostia Antica archaeological site and view the restored Roman villas and tombs. After that, walk across the boulevard to the Piazza Navona, and then cap the night off strolling among the many bars and cafes of Pigneto.