In the background: Church of Santa Maria del Popolo and trees of the Pincio.
The 3,000 year old Egyptian obelisk brought to Rome by Augustus to decorate the
Circus Maximus, is topped with a cross, it was placed here in 1589 by Pope Sixtus V.
I like how you got all that in there, top to bottom and around (while not being at minimum focal
length). Here's a simplified version of these olde obelisks.
http://www.pbase.com/andrys/image/36247712