You can feel like you've stepped back in time when you visit Vaison la Romaine. As the name suggests, this was an important town for the Romans, who liked its location and climate, and built many rather magnificent structures. Vaison became a federated city under the Romans which explains why so many public buildings were constructed.
The most obvious Roman heritage is the Roman bridge (one of only five still standing in Provence), but there are two important excavation sites right in the centre of town - the Site de la Villasse is the biggest archaeological site in France that's open to the public.
You can discover the remnants of Roman villas and wander around their extensive gardens. Just to the north of this site lies the Site de Puymin which includes the grand Antique Theatre (and hosts events during the summer). Some of the ancient Roman artefacts have been collected and are on display in the Musee Theo Desplans.