Students from Langata primary school run past riot police as they protest against a perimeter wall illegally erected by a private developer around their school playground in Kenya's capital Nairobi January 19, 2015. Riot police used teargas to disperse students at a school in Nairobi as the children protested against the potential loss of their playground. The playground was fenced off in December, during the school holidays, by a prominent developer who also claims ownership of the land. The title to the contested site is said to be in the name of Airport View Housing Limited, according to local media, with plans to use the space to build a parking lot for a hotel. (Photo by Thomas Mukoya/Reuters)

Young people fight for fun with their pillows, during the International Pillow Fight Day at the Place des Grottes, in Geneva, Switzerland, Saturday, April 4, 2015. The annual International Pillow Fight Day takes place in hundreds of cities around the world. (Photo by Salvatore Di Nolfi/AP Photo/Keystone)

Elephant fights off hyenas to save baby. “This is the incredible moment an elephant came to the rescue of one of its babies being attacked by a pack of hyenas. The elephant is seen charging at the hyenas to ward them off its offspring. The photos were captured by American photographer Jayesh Mehta, 47, in the Savuti region of the Chobe National Park in Botswana”. Photo: The elephant is seen charging at the hyenas to ward them off its offspring. (Photo by Jayesh Mehta/Caters News)

Chinese woman Zhang Jing, known as the “Ugly Girl” smiles after doctors removed the stitches from her fourth session of cosmetic surgery at a hospital on March 23, 2005 in Shanghai, China. Zhang Jing, 26 years old, from Tianjin Municipality, was forced to leave school because her classmates sneered at her appearance during her teenage years. After leaving junior high school, Zhang found herself still unacceptable by society, she struggled to look for a job, but was turned down by one thousand job applications in ten years. Zhang's story was widely reported by the media in 2003, this helped her find a job and get three chances of free plastic surgery. (Photo by China Photos/Getty Images)

Members of the “Familia Gladiatoria Carnuntina” fight in the historic amphitheatre during the Roman Festival at the archeological site of Carnuntum in Petronell, Austria, June 11, 2016. (Photo by Leonhard Foeger/Reuters)

Members of Japan's idol group “Virtual Currency Girls” wearing cryptocurrency-themed masks perform in their debut stage in Tokyo, Japan, January 12, 2018. Japanese female idols have teamed up to form the ‘Virtual Currency Girls’ group to promote the knowledge of cryptocurrencies through entertainment. Each of its 8 members represents a cryptocurrency: bitcoin cash, bitcoin, ether, neo, nem, ripple, mona, and cardano. (Photo by Kim Kyung-Hoon/Reuters)

Claudia Gadelha (L) of Brazil fights with Jessica Aguilar of Mexico during their Ultimate Fighting Championship (UFC) match, a professional mixed martial arts (MMA) competition in Rio de Janeiro, Brazil August 1, 2015. (Photo by Ricardo Moraes/Reuters)