Puerto Rico's Grace Claxton warms up before competing in the Women's 400m Hurdles Round 1 during the athletics event at the Rio 2016 Olympic Games at the Olympic Stadium in Rio de Janeiro on August 15, 2016. (Photo by Jewel Samad/AFP Photo)

Young woman, 20+, with goose bumps, standing on the beach, Niendorf at the Baltic Sea, Schleswig-Holstein, Germany, Europe on September 1, 2016. (Photo by Alamy Stock Photo)

A model Cindy Bruna presents a creation on a giant catwalk installed on a barge on the Seine River during a public event organized by French cosmetics group L'Oreal as part of Paris Fashion Week, France, September 30, 2018. (Photo by Stephane Mahe/Reuters)

An Afghan man prepares tea for customers at a roadside tea shop on the outskirts of Jalalabad February 2, 2015. (Photo by Reuters/Parwiz)

Artist Emiliano Paolini (R), and his partner Marianela Perelli, show their “Ken” doll that they have re-designed into the religious figure of Jesus Christ at their workshop in Rosario, north of Buenos Aires September 23, 2014. Paolini and Perelli have adapted religious figures such as Jesus Christ, Moses and the Virgin of Guadalupe to Mattel's line of Barbie and Ken dolls and are working on more religious figures, although they say they will not be using the Prophet Muhammad to avoid controversy. They plan to have a gallery show in Buenos Aires next October. (Photo by Enrique Marcarian/Reuters)

A Felix the Cat balloon and other parade floats and balloons are led down Broadway during the annual Macy's Thanksgiving Day Parade; ca. 1900s, Broadway, Manhattan, New York City, New York State, USA. (Photo by Underwood & Underwood/Corbis)

Some are in it just for the money, others to help buy a meal. Then there are those who trade for fun or to spend time among friends. Millions of investors – pensioners, security guards, high-school students – dominate China's stock markets, conducting about 80 percent of all trades. Retirees gather in brokerage houses dotted around China also to enjoy some company and savour the air conditioning on hot days. Some start as young as 13, trading from home with an eye on future careers in finance. Winning isn't guaranteed. This year, among the most turbulent in China's financial history, its stock markets more than doubled in the six months to May, only to crash amid concerns that growth in the country, which makes everything from cars to steel, is slowing faster than previously thought. (Photo by Aly Song/Reuters)

An injured fan is helped by a riot policeman during clashes between Red Star Belgrade and Partizan Belgrade fans in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. Serbian league leaders Partizan Belgrade held champions and bitter city foes Red Star to a 0-0 draw in a derby match marred by bad crowd trouble before kickoff on Saturday. The start was delayed for 45 minutes after home Red Star supporters pelted riot police with seats and flares, forcing officers to retreat from the north tier that houses the club's diehard fans. (Photo by Marko Djurica/Reuters)