A performer entertains the crowd during a rally in support of the leader of the Cameroonian opposition party Movement for the Rebirth of Cameroon (MRC) in Yaounde, on September 30, 2018, prior to the upcoming October 7, presidential elections. (Photo by Marco Longari/AFP Photo)

A Ballet dancer prepares backstage during the final dress rehearsal for the famous Nutcracker ballet by Pyotr Tchaikovsky at the Joburg Ballet, Johannesburg, South Africa, 04 October 2018. The premiere of Nutcracker is scheduled for 05 October and the show will run for two weeks. (Photo by Kim Ludbrook/EPA/EFE)

In this October 7, 2018 photo waitress dance in the Hofbraeu tent after the closing of the Oktoberfest beer festival in Munich, southern Germany, which ran from September 22 through October 7, 2018. (Photo by Felix Hoerhager/AP Photo)

Peter Weiss, director of the Space Department of COMEX, (c) tests a pressurized suit identical to those used in space expeditions in the lava tunnel of “Caverne Gendarme” on October 12, 2018 in Saint-Philippe, the French overseas island of Reunion. Reunion could become a training site for astronauts. (Photo by Richard Bouhet/AFP Photo)

Palestinians scuffle with Israeli forces at Damascus Gate in Jerusalem's Old City on December 8, 2017. Palestinians clashed with Israeli security forces after calls for a “day of rage” as US President Donald Trump's declaration of Jerusalem as Israel's capital sent shockwaves through the region for a second day. (Photo by Thomas Coex/AFP Photo)

School teachers and staff members take part during an active shooter training at James I. O'Neill High School in Highland Falls, New York, U.S., December 12, 2017. (Photo by Eduardo Munoz/Reuters)

People stand near beached sperm whales on January 13, 2016, after they became stranded on the Dutch island of Texel the day before. Five sperm whales which became stranded on Texel have died, officials said January 13. Experts said the beached whales had already been badly injured and their chances of survival were poor. Volunteers tried to save them but called off their efforts late in the night because of bad weather and darkness, ANP news agency said. (Photo by Remko de Waal/AFP Photo/ANP)

Participants of the 79th edition of the annual Christmas swimming “Coupe de Noel” jump into the Lake Geneva, in Geneva, Switzerland, Sunday, December 17, 2017. More than 2000 men and women swam the 120 meters at the traditional Christmas swimming in Geneva where the water temperature was 6 degrees. (Photo by Martial Trezzini/EPA/EFE/Rex Features/Shutterstock)