3 Best Sights in Side Trips from Rome, Italy

In Grottaferrata, a busy village a couple of miles from Frascati, the main attraction is a walled citadel founded by St. Nilo, who brought his group of Basilian monks here in 1004, when he was 90. The order is unique in that it's Roman Catholic but observes Greek Orthodox rites. It is the last surviving Byzantine-Greek monastery in Italy, and has a distinctive blend of art and architecture.

The fortified abbey with its soaring bell tower, considered a masterpiece of martial architecture, was restructured in the 15th century by Antonio da Sangallo for the future Pope Julius II. The abbey church, inside the second courtyard, has glittering Byzantine mosaics and a revered icon of Mary with child set into a marble tabernacle designed by Bernini. The Farnese chapel, leading from the right nave, contains a series of frescoes by Domenichino.

If you make arrangements in advance, you can visit the library, which is one of the oldest in Italy. The abbey also has a famous laboratory for the restoration of antique books and manuscripts, where Leonardo's Codex Atlanticus was restored in 1962 and more than a thousand precious volumes were saved after the disastrous Florence flood in 1966.

Viterbo's Romanesque cathedral was built over the ruins of the ancient Roman Temple of Hercules. During World War II, the roof and the vault of the central nave were destroyed, and you can still see the mark the shrapnel left on the columns closest to the pulpit. Subsequently, the church was rebuilt to reflect its medieval design, and it still has many original details, including a beautiful Cosmati floor that dates from the 13th century.

Three popes are buried here, including Pope Alexander IV (1254–61), whose body was hidden so well by the canons, out of fear that it would be desecrated, that it has never been found. The adjoining Museo del Colle del Duomo has a collection of 18th-century reliquaries, Etruscan sarcophagi, and a painting of the Crucifixion that has been attributed to Michelangelo. The ticket to the museum also grants you entrance to the Palazzo Papale, located on the same square.

Directly across from Palazzo Chigi is the Church of the Assumption, with its distinctive blue dome and round shape designed by none other than Gian Lorenzo Bernini. The artistic architect had his best students execute most of the work of building and decorating the Pantheon-inspired church, creating porticoes outside and an elaborately plastered cupola inside, which steals the show in the otherwise simple interior.