More than 2,000 years old, and still used as a cultural events venue.
The grandeur of ancient Lugdunum
Under the Roman Empire, Lyon (then Lugdunum) was one of the world's most important cities, as capital of Gaul. That came, of course, with various monuments, including the Odéon, a lovely outdoor amphitheatre dating back to circa 15 BC yet still in good enough condition today to host concerts and performances for 10,000 (such as one of Lyon's summer highlights, a theatre, music, and dance festival called Nuits de Fourvière - Fourvière being the hill overlooking the city upon which the amphitheatre is built). Alongside is the Galo-Roman Museum, with a well curated collection of artifacts from that era.