It's 7 o'clock on a school night in Prachinburi, a village outside of Bangkok, Thailand, and hundreds have gathered in a boxing arena to watch children beat the living daylights out of each other.
Many boys and girls, between the ages of 7 and 9, participate in a form of boxing known as Muay Thai. These kids compete for money, often through widespread gambling -- bets placed on who will win.
During their fights, which occur almost every night of the week, these kids don't use head gear, mouth guards or any other form of protection. All they wear are shorts and a pair of boxing gloves. Even at this young age, many have been training for years.
This isn't some secret backroom sport, but a national pastime in Thailand, fully engrained in Thai culture, mainly in poor communities. But this form of fighting can have dangerous consequences. Videos of these fights have captured some disturbing moments, including a child vomiting in the ring, crying and wanting to quit, only to be sent back in. In another video, a little girl's eyes can be seen rolling back into her head. Doctors say she suffered a seizure from the blows she took.
In this surreal scene of pint-sized boxers, ABC News met a stone-faced 7-year-old named Andy, who was preparing for his first fight.
When asked if she was worried about her son getting hurt, Andy's mother said through a translator that "I'm not scared ... because I want to teach him to be tough."
Andy said he liked to fight, "because I get money," but his first match didn't last long. The refs called it off early, fearing the little boy was outmatched by his opponent.
A 9-year-old girl named Poomrin is typical of many of the young fighters. After school she heads to a makeshift boxing ring built atop of a crumbling old dock along a river. She has 15 brothers and sisters -- and all of them fight. Poomrin and her 15-year-old sister Pavida said they have had their lips cut and teeth broken in the ring.
Poomrin said she had been in 11 fights and won all of them. Her sister said she has fought 41 and lost half of them.
Their training is endless. Fighters jog every day, exercising and drilling repeatedly. Even the smallest children are expected to join in. The girls' father, a former fighter himself, said he had no concerns about his children's safety in the ring. Their proud mother showed off the family's overflowing stash of trophies and prizes.
"It's a sport and there are bigger problems," Poomrin's mother said through a translator, adding that it keeps the kids happy, focused and away from drugs.
Many families believe fighting keeps kids away from other dangers, and in this culture, there are few alternatives for success. Some of these kids would be working in sweatshops or put to work in Bangkok's infamous red light district if they weren't in the ring.
Filmmaker Todd Kellstein spent years inside Thailand's child boxing culture for his film, "Buffalo Girls," which follows the lives of two young girls whose families rely on them to win in the ring and bring home money. Kellstein said watching families place bets and encourage their children to fight in the ring was difficult for him to watch at first.