Start your 'Rome in Day' tour with the city's most famous ancient monument – the Colosseum. Walk through the interior and try to imagine the gladiator battles that took place there. Visit the nearby Roman Forum to see the Temple of Saturn, House of the Vestal Virgins and the Arch of Titus among other things. Go from ancient Roman monuments to modern ones with a stop at the Vittoriano on Piazza Venezia.
Throw a coin into the water when you reach the Trevi Fountain to ensure your return to Rome. Stop for lunch (own expense) at one of the restaurants in the area before heading on to the Government District. See the Palace of the Council of Ministers, the Parliament and the Column of Marcus Aurelius.
See the Temple of Hadrian on your way to the Pantheon, where you'll see tombs of Italian kings as well as the artist Raphael.
Continue on to the Ancient Baths of Nero and then to Piazza Navona to see Bernini's famous fountain in its center.
Visit the Vatican as your final stop. See the highlights in the enormous Vatican Museums, including the Raphael Rooms and Michelangelo's frescoes in the Sistine Chapel.