Here is a modern “Sphere Within Sphere” sculpture by Pomodoro in the courtyard of the Vatican Museum. In addition to a major collection of artworks, including impressive maps of the world, the museum also serves as the entrance to see the Sistine Chapel. Note that the entrance to the museum is on the outside of the walls of Vatican City and is not accessible from within the piazza in front of St. Peter’s (and it’s a long walk around!)