Prisons in Thailand stage Muay Thai (a form of kickboxing) matches between inmates and foreign fighters to entertain prisoners and to promote good health. The fighters can also reduce their their sentences, and perhaps even win freedom, by doing well in bouts.

Getty Images photographer Borja Sanchez-Trillo visited Klong Pai prison in Nakhon Ratchasima to document the event known as "Prison Fight".

An inmate and a foreign fighter pose before their fight at Klong Pai prison
An inmate and a foreign fighter pose before their fight at Klong Pai prisonBorja Sanchez-Trillo/Getty Images
An inmate kicks a foreigner fighter in the face during their bout
An inmate kicks a foreigner fighter in the face during their boutBorja Sanchez-Trillo/Getty Images
An inmate trains before his fight at Klong Pai prison
An inmate trains before his fight at Klong Pai prisonBorja Sanchez-Trillo/Getty Images
Foreign fighters watch a Muay Thai fight before their bouts
Foreign fighters watch a Muay Thai fight before their boutsBorja Sanchez-Trillo/Getty Images
Inmates react during a Muay Thai fight at Klong Pai prison
Inmates react during a Muay Thai fight at Klong Pai prisonBorja Sanchez-Trillo/Getty Images
An inmate shows a 'Round 1' banner during a fight at Klong Pai prison
An inmate shows a 'Round 1' banner during a fight at Klong Pai prisonBorja Sanchez-Trillo/Getty Images
A foreign fighter and an inmate compete during a Muay Thai fight at Klong Pai prison
A foreign fighter and an inmate compete during a Muay Thai fight at Klong Pai prisonBorja Sanchez-Trillo/Getty Images
A foreign fighter warms up before his fight
A foreign fighter warms up before his fightBorja Sanchez-Trillo/Getty Images
Assistants massage an inmate before his fight, as a prison officer stands by
Assistants massage an inmate before his fight, as a prison officer stands byBorja Sanchez-Trillo/Getty Images
An inmate is helped after he falls to the floor during a Muay Thai fight
An inmate is helped after he falls to the floor during a Muay Thai fightBorja Sanchez-Trillo/Getty Images
An inmate stretches before his fight, while a officer stands guard at Klong Pai prison
An inmate stretches before his fight, while a officer stands guard at Klong Pai prisonBorja Sanchez-Trillo/Getty Images
Blood is seen on an inmate's boxing glove as he rests during a Muay Thai fight
Blood is seen on an inmate's boxing glove as he rests during a Muay Thai fightBorja Sanchez-Trillo/Getty Images
A bloodied inmate receives treatment during a break between rounds
A bloodied inmate receives treatment during a break between roundsBorja Sanchez-Trillo/Getty Images
A prison officer holds rounds indicator signs before fights begin
A prison officer holds rounds indicator signs before fights beginBorja Sanchez-Trillo/Getty Images