Start at the Colosseum for a timed entry around 8:30–9:00, before the stone arena becomes intensely hot and the crowds build. Allow about 1½ hours, including security; bring water and arrive 15–20 minutes early. Standard combined tickets covering the Colosseum, Roman Forum, and Palatine Hill generally cost around €18, though special arena or underground access costs more. From Termini, take Metro B to Colosseo; if you’re staying centrally, walking is often just as pleasant.
Continue directly into the Roman Forum and Palatine Hill, allowing roughly two hours for the uphill paths, temples, and panoramic viewpoints. There is little shade, so a hat and comfortable shoes matter more than they seem. Exit toward Via dei Fori Imperiali and walk a few minutes into Monti for lunch at La Taverna dei Fori Imperiali. Reserve if possible, and expect approximately €25–€40 per person for Roman classics such as carbonara, amatriciana, or cacio e pepe. The restaurant is closed on some holidays and typically has a mid-afternoon break, so aim for lunch around 12:30–1:00.
After lunch, stroll west through Monti and along Via dei Fori Imperiali toward the Pantheon—about 25 minutes at an easy pace, or take a short taxi if the heat is punishing. The Pantheon usually opens from morning until early evening, with paid entry of roughly €5; dress respectfully, as it remains a consecrated church. Spend about 45 minutes inside, then wander through the surrounding lanes to Piazza Navona, best enjoyed in the softer late-afternoon light. Give yourself another 45 minutes to admire Bernini’s Fountain of the Four Rivers and the street life around the square; avoid the most prominent cafés if you want better value.
Finish with dinner at Roscioli Salumeria con Cucina near Campo de’ Fiori, around a 10-minute walk from Piazza Navona. This is a booking-essential restaurant, particularly for the famous pasta counter, and dinner usually runs €40–€70 per person before extensive wine choices. Reserve for around 7:30–8:00, and leave room for the cured meats and a Roman pasta rather than trying to order everything. Afterward, the historic center is wonderfully walkable, with taxis or buses available from Largo di Torre Argentina if you prefer not to walk back.