Funny, first place I thought about was St. Patrick's Cathedral.
Didn't Peggy Noonan see middle-eastern men taking pictures of St. Pat's a few months ago?
It would be a wise decision to close down the cathedral and guard it heavily until after the convention. Mass could be held in the chapel or a neighboring parish.
I wonder, do they have concrete barriers around it yet?
On TM we have been discussing attacks on the Vatican for weeks, this is coming down to the wire, I hope they have a response prepared!!!