If you're new to Rome, and have no idea where to start, I recommend swallowing your pride and getting a ticket for one of the Big Bus Sightseeing Tours. These can be purchased at the main bus terminus in Rome. Once you're on the bus, you'll be taken round ALL of the sights, and you can hop on and off etc. And no, I don't work for this company, and this isn't a marketing ploy; I just found it an invaluable way to plan your attack on this beautiful city.
Main Bus Station - Rome
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