Enjoy the art in Italy
It's easy to get distracted by the old sites, shopping, and restaurants when visiting Italy. However, ignoring the art scene, both from the Renaissance and today, would be a huge error. There are around 100 art galleries in the Vatican (not to mention The Sistine Chapel ceiling, painted by Michelangelo).
The Peggy Guggenheim Collection in Venice houses a large number of modern artwork by Picasso and Magritte. Botticelli's Birth of Venus, much imitated but never copied, hangs in Florence's Uffizi Gallery. You should remember that enjoying the art in Italy is one of the top Things about Italy You Should Know.
Whether or not you agree with the Catholic Church's views, visiting the Vatican Museums, the Sistine Chapel, St. Peter's Basilica, and the Vatican Gardens requires respect. A rigorous dress code prohibits visitors from wearing low-cut or sleeveless apparel, shorts, miniskirts, or headgear. Basically, you should cover your shoulders and knees. Also forbidden? Selfies are irreversible.