Battle of the Oranges (Carnevale di Ivrea)

Nine carts of costumed "orange throwers" and thousands of unarmed pedestrians face off across the piazzas of Ivrea in a reenactment of a 19th-century revolt against a tyrant — restaged, every year, with 500 tons of actual oranges thrown at genuinely violent full-contact speed. This is not a gentle food fight. People get hurt. The carts come at you.

There is exactly one rule that keeps you safe as a spectator, and it is non-negotiable: wear the red Phrygian cap, the berretto frigio, sold all over town, and you are marked as a non-combatant the throwers are supposed to leave alone. Skip it, wander into a piazza during a battle, and you will get pelted — that's not an edge case, it's the mechanic working as designed. Buy the hat before you do anything else.

100,000-plus visitors show up for this, Turin is an easy train ride away, and spectating solo among that many people is entirely unremarkable — you're one more red-hatted onlooker at the edge of a battle nobody expects you to join unless you've paid €20–100 and bought the mandatory €75 protective kit to throw with a team. Do that only if you know what you're signing up for.