Scavi Tour
I haven't heard of it before until I did my research, but apparently, there is an excavation tour at St Peter's Basilica at the Vatican. You get to walk through the catacombs under the basilica with a small group and only a couple hundred people get accepted a day. I decided to write to the excavation office just to see what would happen. I read that some people didn't hear back for at least a couple months and others don't hear back at all. I was lucky enough to get a reply after a week and I got a spot. Happy it was the first group in the morning too, since it makes it easier on planning out the rest of the day and making reservations for the Vatican museums. Now I need to figure out if I want to see more catacombs or if one will be more than plenty.