Thank you. When I was in Rome in mid-August '99 I walked from the Vatican to the Capitoline (several miles) in 95 degree weather wearing loafers, khakis and a blue oxford shirt. I didn't melt or pass out.
I saw St. Peter's, the Vatican Museum, the Lateran, the Pantheon, the Coliseum, the Circus Maximus, the Gesu and other important places and managed just fine with a little water and a little gelato along the way.