I can't make out on my monitor what is at the very bottom. It looks an individual maybe shooting the opposite shot you've taken. Someone appears to be on the floor and shooting upward.
-T
This is a really cool image . . . I have virtually the same image, though without people in it. Just out of curiosity, when did you make this image? I was there this past June on the 30th . . . quite the coincidence! I'd post mine, but don't wish to intrude.
I was one of the first people in the Vatican Museum and I knew I wanted this shot, so I quickly got here before the crowds arrived to descend the stairs and exit.
Nikon D4 & 14-24 mm f2.8 @ 14 mm/f9 (not sure why f9 was selected - too big a hurry I guess)