In the southern part of town, the carefully restored Théâtre Antique, place des Frères-Mounet (tel. 04-90-51-17-60; www.theatre-antique.com), dates from the days of Augustus. Built into the side of a hill, it once held 8,000 spectators in tiered seats. The theater is nearly 105m (345 ft.) long, 38m (125 ft.) high, and noted for its acoustics. It's open daily: November to February 9:30am to 4:30pm, March and October 9:30am to 5:30pm, April to May and September 9am to 6pm, and June to August 9am to 7pm. Admission is 7.70€ ($10) for adults, 5.80€ ($7.55) for students and children under 18.
West of the theater stood a huge temple that, along with a gymnasium, formed one of the greatest buildings in the empire. Across the street, the Musée Municipal d'Orange, place du Théâtre-Antique (tel. 04-90-51-17-60), displays fragments of the temple. Your ticket to the theater also admits you to the museum, which is open daily April through September 9:30am to 7pm, and October through March 9am to 5:30pm.
Even older than the theater is the Arc de Triomphe, on avenue de l'Arc-de-Triomphe. It has decayed, but its decorations and other elements are fairly well-preserved. Built to honor the conquering legions of Caesar, it rises 22m (72 ft.) and is nearly 21m (69 ft.) wide. Composed of a trio of arches held up by Corinthian columns, it was used as a dungeon in the Middle Ages.
Before leaving Orange, head for the park Colline St-Eutrope, adjacent to the Théâtre Antique, for a view of the valley and its mulberry plantations.
After exploring the town, drive south for 13km (8 miles) along A9 to Châteauneuf-du-Pape, where you can have lunch (Tues-Sun) at the Hostellerie du Château des Fines-Roches, route d'Avignon (tel. 04-90-83-70-23; www.chateaufinesroches.com). Although the hostellerie was built in the 19th century, its medieval features make it appear feudal. If you're pressing on to Avignon, it's only another 13km (8 miles) south along any of three highways (each marked AVIGNON).