Visit the Tomb of St. Peter (under St. Peter's Basilica, Rome)

Back in 2004, I took my first trip to Rome, and this tour, known as the "Scavi tour" was among the highlights.  It is a trip to the necropolis (where the dead were buried centuries ago) that is located under St. Peter's Basilica.  This video and slide show takes you down to the Roman "street level" back in the apostolic age.  Although it doesn't have all the cool narration that a live tour would give you, and that's a shame.  But it does give you a virtual tour of the site... but first, you must get used to moving around the site using the arrows and markers the tour gives once you get to the "underground" portion of the tour.

Centuries ago, when Constantine filled in the necropolis to build the basilica over St. Peter's tomb, he probably ticked off a lot of the locals.  However, centuries later, after several archeological digs, we have a marvel that preserves the spot where Peter's body was laid, as well as a historical record.