Nobody in the eastern Spanish village of Bunol knows for sure how the world's biggest tomato war began.
In August 1945, a scuffle broke out between young members of a carnival crowd, the official version has it.
Fruit stalls were overturned, and one of them happened to be full of tomatoes...
Sixty-five years later, the tomato fight known as Tomatina has ballooned into one of Spain's most popular summer fiestas, drawing tourists from all over the world into the village of 10,000 residents.
'We expect about 45,000 visitors for this year's Tomatina,' Bunol culture official Pilar Garrigues told DPA.
She dismissed criticism by some locals that the event was becoming a victim of its own success, with the village becoming so crowded that the Tomatina was not as much fun any more.
'This fiesta is in our blood,' Garrigues said. 'We are proud of the Tomatina, which has put Bunol on the world map.'
On the last Wednesday of August, lorries dump more than 100 metric tonnes of tomatoes into several places in the village centre. The explosion of a firecracker then acts as a war cry.
One hour later, as a second firecracker signals the end of the battle, the participants have literally painted the town red.
Bedraggled, often shirtless, tomato warriors head for temporary showers, while armies of cleaners using hoses and fire engines prepare to move into streets covered with squashed tomatoes and lined with splattered buildings.
'Most of the participants are young men, but there are also women and elderly people. Everyone wants to join the Tomatina,' said a source at the Bunol town hall.
'It allows you to do something really different. It gives you a massive adrenaline high,' she describes her experience of the fight.
The rules order participants to squash the tomatoes before throwing them, and ban the use of any other weapons. However, the latter rule is often ignored as people tear off their wet t-shirts and hurl them at each other.
Many of the fighters, however, take precautions such as wearing goggles, while shopkeepers cover their storefronts with plastic sheets to protect them.
Garrigues said she was aware of only one serious accident during the Tomatina. That occurred in 2002, when a drunken woman tried to climb on board a tomato lorry and the vehicle ran over her leg.
'Health workers usually treat people only for minor mishaps, such as getting tomato juice in their eyes,' the culture official said.
When the first Tomatina erupted spontaneously in 1945, police arrested the participants and reportedly even tried to make them eat the ruined tomatoes - without success.
The regime of 1939-75 dictator Francisco Franco tried to ban the event for its first 12 years, fining and locking up participants.
But local people staged protests - including a 'funeral procession' which featured a coffin with a tomato inside - until the regime was finally forced to concede defeat, and the Tomatina became legal in 1957.
It now forms part of Bunol's 10-day annual festival in honour of the village's patron Saint Luis Bertran, and has soared to become one of the highlights of Spain's countless summer fiestas, which range from bull runs to mock historic battles.
Bunol spends about 90,000 euros ($136,000) annually on the Tomatina, including the cost of the tomatoes, toilets and showers, cleaning and health personnel, Garrigues estimated.
'The Tomatina brings business to bars, restaurants and souvenir shops,' she pointed out.
Bunol's two hotels and rural hostels in the area are fully booked long in advance, forcing most visitors to lodge in the nearby city of Valencia.
However, Bunol organises the Tomatina for fun and fame, rather than for financial gain. 'The Tomatina is known as far as South Korea, where a university included the event in its tourism textbooks,' Garrigues says with pride.
'Residents not only participate in the fight, but volunteer to watch over fighters' bags and help clean up the mess afterwards,' she explained.
Not everyone in Bunol, however, is as enthusiastic.
'In earlier times, the tomato fight sometimes gave you the chance to take aim at someone you disliked,' a female participant said. 'But now it has grown so massive that it is impossible to get close to anyone particular any more.'