Horse racing is part of Naadam, a festival organized every July in Mongolia to celebrate the People’s Revolution. Using children as jockeys in such races has a centuries-long tradition. Boys and girls as young as 5 (although the law imposes a minimum age limit of 7) ride in races that can be dangerous, with hundreds of horses running across the steppe at distances of 12 to 28 kilometres at great speeds. (Photo by Tomasz Gudzowaty)

A young man, who says he is part of a local criminal gang, poses for a picture holding a gun in the neighbourhood of Korogcho in Nairobi, Kenya, March 19, 2015. Around 2 million people live in the shantytowns packed in around Kenya's capital. Crime is high amid chronic unemployment levels, while basic services and sanitation are scarce. Residents try to make the best of things, eking out a living and picking up work where they can. (Photo by Siegfried Modola/Reuters)

An American flag flutters on a young tree stripped of bark after a massive tornado passed through the town killing at least 116 people May 24, 2011 in Joplin, Missouri. The tornado that ripped through the town of about 50,000 people May 22, is being called the deadliest single tornado in the U.S. in 60 years. (Photo by Julie Denesha/Getty Images)

Tens of thousands of HIV positive prostitutes in the slums of Lagos to ensure a rapid spread of the epidemic. “If you arrive by car, you can smell the HIV virus outside”, joked my driver as we are on track to Badia a criminal slums of Lagos. Badia is a corruption of “Bad Area”. Nigerians have a lack of everything, except black humor. The poor West African country Nigeria, with a population of 140 million people, after India and South Africa the highest number of people with HIV / AIDS. (Photo by Ton Koene/Exclusivepix Media)

Kanphitcha Sungsuk, 21, (C), lines up with young men to speak to officers during an army draft held at a school in Klong Toey, the dockside slum area in Bangkok, Thailand, April 6, 2017. Thailand is widely seen as a paradise for gay and transgender people, but many complain of being treated as second-class citizens and the obligation to respond to the draft can be a nightmare when they turn 21. (Photo by Athit Perawongmetha/Reuters)

Young dancers from the Style Dance Academy perform during a Mother's Day block party in Caracas, Venezuela, Sunday, May 19, 2019. Although Mother's Day was officially celebrated the previous weekend, people in the Petare area organized the neighborhood party to celebrate the mothers of their community. (Photo by Rodrigo Abd/AP Photo)

Young women sit at a doorway during the annual San Antonio Abad (Saint Anton Abbott) festival in Trigueros, southwest Spain January 25, 2015. Thousands of people arrived in Trigueros to participate in this annual catching of food and presents, part of a traditional three-day religious festival. (Photo by Marcelo del Pozo/Reuters)

For the Torajan people of Indonesia, death is part of a spiritual journey: families keep the mummified remains of their deceased relatives in their homes for years – and traditionally invite them to join for lunch on a daily basis – before they are eventually buried. Here: Todeng died in 2009. A young relative of his, Sam, lights him a cigarette and changes his glasses. (Photo by Claudio Sieber Photography/The Guardian)