Lyon (Lugdunum) was originally founded as a Roman city in 43 BC, strategically located atop Fourvière Hill, with views across the Rhône and Saône rivers. Though much of the original city has long since been paved over, the beauty of this Gallic stronghold can still be appreciated at two massive stone theaters built into the hillside.
The larger Gallo-Romain Theater, dated to 15 BC, is Gaul's oldest, built for the enjoyment of musical and theatrical performances. The smaller but more opulent Odéon, next door, was built around 161 AD, using precious marbles and other exotic materials imported by the increasingly affluent city's upper crust.
In addition to the atmospheric ruins, onsite Musée Gallo-Romain exhibits intriguing artifacts from the city's long history, including sculptures, paintings, an even a bronze transcript of a speech given by Emperor Claudius, himself born in Lyon, demanding equal rights for Gallic citizens of the empire.
Both of the theaters are free and open daily, while the museum is free to the public on Thursdays only, and closed Monday. While athletic types will enjoy the climb up Fourvière Hill, you can also take the Fourvière Finuncular from the Vieux Lyon metro station.
If you'd like to enjoy the theaters' still superb acoustics, watch as modern performers take to the ancient stages every summer, during the Nuits de Fourvière.