La Tomatina, the world’s largest tomato-throwing festival, is held on the last Wednesday of August every year. This year, it falls on Aug. 30.

This year marks the 72nd anniversary of the wacky festival. Up to 22,000 revelers are expected to gather for the festivities with 165,000 kilos of tomatoes in the tiny Valencian town of Buñol on the east coast of Spain.

GettyImages-598035924 Revelers, covered in tomato pulp, participate in the annual 'tomatina' festivities in the village of Bunol, near Valencia, Aug. 31, 2016. Photo: Getty Images

There are numerous stories surrounding the origin of the festival. According to La Tomatina’s official website, it was said to have begun at a parade in 1945. A fight broke out among a crowd of young people at the parade, and they ended up near a market that was selling vegetables. The young people then started throwing tomatoes at each other until local forces intervened and ended the fight.

A year later, some young people again brought tomatoes and other vegetables from their houses in order to fight, and thus the tradition was said to have been born. 

Other theories of how it began, according to Barcelona-Life.com, include, "the rubbishing of a bad musician," "throwing of tomatoes at politicians at a democratic protest," and "the ensuing aftermath of an accidental truck spillage." Barcelona-life.com is a travel website that guides tourists to choose from the best places to eat, sleep, drink, shop, and visit in Barcelona.

Under the administration of dictator Francisco Franco in the 1960s, La Tomatina was banned because it had no religious significance. San Luis Bertran, the local patron of the town of Buñol, started organizing the event after Franco’s death in 1975. He also supplied the tomatoes for the locals to throw at each other. However, it wasn’t until 1980 that the local council in the town took control of the event, and thus the modern day La Tomatina festival was born.

GettyImages-485246998 A reveler has a bucket of tomato pulp emptied over him during the annual 'tomatina' festivities in the village of Bunol, near Valencia, Aug. 26, 2015. Photo: Getty Images

There is a tradition that is followed before the tomato fight. A person is supposed to climb a large and greasy pole in the town square and has to retrieve a ham that is placed at the top of the pole. This ritual happens around 11 a.m. local time (5 a.m. EDT), according to latomatinatours.com.

Participants are required to buy tickets for the event so that the local government is able to control the size of the crowd as the annual festivity attracts people from all over the world.

Shopkeepers along the festival street also cover their shop-fronts with sheets of plastic in order to keep out the mess. After the tomato fight is over, large trucks with hoses are used to wash down the streets and also the participants. The participants also sometimes take a dip in the local rivers to clean themselves up.

GettyImages-485248414 Revelers enjoy the atmosphere in tomato pulp while participating the annual 'La Tomatina' festival in Bunol, Spain, Aug. 26, 2015. Photo: Getty Images

GettyImages-178255295 Participants covered with tomato pulp take part in the annual Tomatina festival in Bunol, Spain, Aug. 28, 2013. Photo: Getty Images

In 2002, La Tomatina was named as a "Festivity of International Tourist Interest" by Spain’s tourism secretary because of its huge success among people around the world, according to the official website of the festival.

La Tomatina has become so famous through the years that it has inspired similar celebrations around the world. For instance, in Colombia, the town of Sutamarchán has been conducting a tomato fight in the month of June since 2004. Similarly, in the United States, Twin Lakes, Colorado, began the "Colorado-Texas Tomato War" in 1982. The food fight is held in the month of September every year among the residents of Texas and Colorado. Similar annual events are held in Costa Rica and Chile, according to Heavy.com.