St. Peter's Basilica Dome Tour

While visiting St. Peter's Basilica is an excellent experience, going on the dome tour makes it ten times better. Yes, it costs some money (7 Euros) and you'll need to climb over 300 steps. However, the view at the top inside the basilica, as well as outside the basilica is well worth it. You'll get a great view of Vatican City and Rome from this vantage point that you can't get anywhere else.

Be aware, if you have health issues climbing stairs though, this is not something to do.