Tradition says that once the tomato supply runs dry, the revelers jump into a nearby river en masse, while the fire brigade hose off the streets.
"La Tomatina" is rumored to have started in the 1940s when a group of young friends began throwing their lunch at each other one day, near a vegetable stand on the town square. They met again the next year and pelted each other — and passers-by — creating the annual tradition.