Here's an ideal itinerary for 3 days in Rome that will allow you to explore the city at a relaxed pace:

Day 1:

• Start your day with a visit to the Colosseum, one of the most iconic landmarks in Rome. You can take a guided tour or explore on your own.
• After the Colosseum, head over to the Roman Forum and Palatine Hill, which are located nearby. These ancient ruins offer a glimpse into the history of Rome.
• For lunch, head to Trastevere, a charming neighborhood known for its narrow streets and delicious food. There are plenty of restaurants and cafes to choose from.
• In the afternoon, visit the Pantheon, a stunning temple dedicated to all the gods of Ancient Rome. It's free to enter and is open until late in the evening.
• End your day with a stroll through Piazza Navona, a beautiful square with fountains and street performers.

Day 2:

• Start your day with a visit to Vatican City, the smallest country in the world. You can take a guided tour of the Vatican Museums, Sistine Chapel, and St. Peter's Basilica.
• For lunch, head to Campo de' Fiori, a bustling market square with plenty of food options.
• In the afternoon, visit the Spanish Steps, a popular spot for tourists and locals alike. From there, you can walk to the Trevi Fountain, another must-see attraction in Rome.
• End your day with a leisurely walk along the Tiber River, where you can enjoy views of the city and watch the sunset.

Day 3:

• Start your day with a visit to the Borghese Gallery, a museum housed in a beautiful villa with stunning gardens. You'll need to book tickets in advance.
• For lunch, head to Testaccio, a neighborhood known for its street food and local cuisine.
• In the afternoon, visit the Appian Way, an ancient road that was once used to transport goods and soldiers. You can rent a bike or take a guided tour.
• End your day with a visit to the Baths of Caracalla, an impressive complex of Roman baths that date back to the 3rd century AD.

I hope this itinerary helps you plan your trip to Rome! Let me know if you have any questions or need further assistance.