The Passetto » Secret Papal Passage

Escape route between the Vatican and Castel Sant' Angelo

Would you like to know what's that corridor,
Covered here and there by a small roof,
That runs from St. Peter's to the Castle,
Where sometimes the air is fresher?

I'll tell you in short:
Our Lord keeps it for his personal use,
In the case one of his whims
Makes him feel like playing hide and seek...
- Giuseppe Gioachino Belli, 1845

Angels & Demons map of Rome: Path of the Illuminati