At first glance, there hardly seems to be any comparison between Ravenna and Rome, but back in the 5th century, it was Ravenna that served as capital of the Western Roman Empire. In this city, Roman rulers built monuments which are famous, then and now, for their sweeping mosaics（键嵌图案）. Seven of Ravenna's eight buildings from the 5th and 6th centuries are spectacularly decorated with examples of this ancient art. "In the past, many people couldn't read or write," says tour guide and Ravenna native Silvia Giogoli." Mosaics were a way to explain the religion and the political situation to the people."Visitors to Ravenna can look at pieces of art by ancient artists, listen to musicians, and learn to make their own masterpieces.Travel TipsWhen to Go: June—October; weather is pleasant in April and May but historic sites can get crowded with school groups.Where to Stay: Walk through historic district sites from Albergo Cappello and stay at a modern Hotel Centrale Byron.How to Get Around: Take the train from Bologna, and then walk, bike, or use taxis within the city.Where to Eat or Drink: Housed in a former movie theater, two-story Ristorante Cinema Alexander blends 1940s Hollywood flavor with homemade Emilia Romagna courses and attentive service (helpful in translating the menu). For fresh seafood, try Osteria L'Accigua and Da Buco.What to Buy: Watch the next generation of Emilia Romagna mosaic artists create contemporary and traditional pieces in local studios where modern artists use the same methods as their Byzantine forefathers.What to Read Before You Go: Ravenna in Late Antiquity, by Deborah Mauskopf Deliyannis（2010）, provides a wide-ranging look at the city's art, architecture, and history.In ancient times, mosaics were used to _____.