The best-preserved Roman amphitheater in the world and the best known in Italy after Rome's Colosseum, the elliptical Arena was built in a slightly pinkish marble in the 1st century A.D. and stands in the very middle of town, with the Piazza Brà on its southern flank. Built to accommodate more than 20,000 people (outdone by Rome's contender that could seat more than twice that), it is in remarkable shape today (despite a 12th-c. earthquake that left only four arches of the outer ring standing), beloved testimony to the pride and wealth of Verona and its populace.
Its acoustics (astoundingly good for an open-air venue) have survived the millennia and make it one of the most fascinating venues for live performances today, conducted without microphones. If you're in town during the summer opera performances in July and August, do everything possible to procure a ticket for any of the outdoor evening performances. Even opera-challenged audience members will take home the memory of a lifetime. Other events, such as orchestral concerts, are staged here whenever the weather permits. Check with the tourist office for more information.
The cluster of outdoor cafes and trattorie/pizzerias on the western side of the Piazza Brà line a wide marble esplanade called Il Liston; they stay open long after the opera performances end. Enjoy some serious post-opera people-watching here.