A prisoner from the Pedrinhas prison is carried to receive medical help after he was injured during a fight between rival gangs inside the jail, in Sao Luiz, capital of Maranhao state, January 8, 2014. The recent posting on a major Brazilian news website of a video filmed last December 17 by Pedrinhas prisoners of the decapitated and tortured bodies of rival inmates inside the jail has highlighted some of the problems present in the country's prison system which houses nearly twice as many prisoners as its capacity, according to official statistics. (Photo by Douglas Cunha/Reuters/O Estado do Maranhão)

Students exercise in body training at Bishan Vocational Education Center in Chongqing, southwest China, January 13, 2016. These students were trained to be stewardesses of the high-speed train. (Photo by Xie Jie/Xinhua)

A jockey falls from his buffalos during Barapan Kebo or buffalo races as part of the Moyo festival on September 30, 2014 in Sumbawa Island, West Nusa Tenggara, Indonesia. The traditional Buffalo races, known as Barapan Kebo, are held by Samawa tribes in muddy rice fields to celebrate and provide entertainment ahead of the annual planting season. Jockeys secure themselves on a wooden structure attached to the buffalo, and maneuver across the mud in a race to the finish line. The jockeys weild long sticks, in a similar style to jousting, and direct them towards targets called “Saka”. (Photo by Ulet Ifansasti/Getty Images)

Lightning strikes the Willis Tower (formerly Sears Tower) in downtown on June 12, 2013 in Chicago, Illinois. (Photo by Scott Olson/Getty Images)

Two baby orangutans play with each other at the wildlife department in Kuala Lumpur, Malayasia, October 19, 2015. The Malaysian wildlife department in July seized two baby Sumatran orangutans, found in duffel bags, from traffickers who were attempting to sell them to buyers in Malaysia. According to local media, the orangutans will be returned to Medan, Indonesia on Tuesday. The illegal wildlife trade is estimated to be $8 billion a year worldwide, according to TRAFFIC, a wildlife trade monitoring network. (Photo by Olivia Harris/Reuters)

A man presents a self-made robot that local media reported is able to carry a person, in Heihe, Heilongjiang province, China, April 5, 2017. (Photo by Reuters/China Daily)

An animal advocate lays in fake blood in a replica of a meat package with a label that reads “meat” during a protest “The meat is murder” in the Bulgarian capital Sofia on May 8, 2016. (Photo by Nikolay Doychinov/AFP Photo)

Women wearing traditional hats, known as a non la, sell fruits in Hoi An, Vietnam April 4, 2016. The non la hats are made of readily available materials such as palm leaves, tree bark and bamboo and are visible everywhere in the city, a UNESCO World Heritage site. Hoi An's history as a busy trading port is evident throughout its architecture, a mix of eras and styles, with traditional wooden Vietnamese houses, Chinese temples and French colonial buildings. (Photo by Jorge Silva/Reuters)