The Theatre de l'Archeveche is an outdoor stage tucked into the courtyard of the old archbishop's palace, beside the cathedral. For most of the year it sits quiet, but every July it becomes the centrepiece of the Festival d'Aix-en-Provence — one of the great opera festivals in Europe, founded in 1948, with productions that regularly tour to La Scala and the Met.
Even outside festival season the courtyard is worth a glance through the gates. If you can time your visit to the festival, do it: tickets run from generously priced to eye-watering, the staging is famously inventive, and a warm summer night under the Provencal sky with a first-rate opera in front of you is one of the more memorable evenings a traveller can have in France.