An Army Sikorsky R-5 helicopter, undergoing record trials, demonstrates its lifting power by carrying 17 persons and pilot aloft as female onlookers wave in Bridgeport, Conn., January 10, 1946. During the tests records were claimed for altitude speed and both altitude and speed with payload. (Photo by Anthony Camerano/AP Photo)

Contestants congratulate Chelsea Morgensen (R) of Hollywood, California as she is crowned Miss Hooters International 2017 during the 21st Annual Hooters International Swimsuit Pageant at The Pearl concert theater at Palms Casino Resort on July 12, 2017 in Las Vegas, Nevada. (Photo by Alamy Stock Photo)

Participants pose as they take part in a bodybuilding and fitness event named “China Fit”, in Beijing, China, June 15, 2016. (Photo by Reuters/Stringer)

The Rio de Janeiro Olympics kick off on August 5 for some two weeks of competitive games drawing athletes as well as audiences from around the world. As they prepare to cover the event, Reuters photographers look back on their favourite pictures from past Olympics where they captured the action on the ground as well as the participants' tears and joy that followed. (Photo by Lucy Nicholson/Reuters)

Labourers carry a basket packed with vegetables through a wholesale market in Kolkata, India, February 26, 2016. (Photo by Rupak De Chowdhuri/Reuters)

Schoolchildren play music to entertain and inspire people on their way home from work Tuesday, March 29, 2016 in Pyongyang, North Korea. North Korea has called a 70-day loyalty drive areas of a major congress of the ruling party scheduled for early May and everyone from students to coal miners have been mobilized nationwide to demonstrate their devotion to the leadership. (Photo by Eric Talmadge/AP Photo)

An abandoned tank left by Boko Haram, February 20, 2016, seen on the road to Michika, Nigeria – a town formerly occupied by the insurgents. On April 14, 2014, 300 schoolgirls in the Chibok village in Nigeria were kidnapped by the terrorist group, Boko Haram. Two years later, the majority of these girls are still missing. According to the Global Terrorism Index Report 2015, Boko Haram, which operates mainly in Nigeria, has become the most deadly terrorist group in the world. (Photo by Danielle Villasana)

Kelsey Smith of New Zealand gets her stick caught on the shorts of Hollie Pearne-Webb of England during Women's Semi Final Hockey match between England and New Zealand on day eight of the Gold Coast 2018 Commonwealth Games at Gold Coast Hockey Centre on April 12, 2018 on the Gold Coast, Australia. (Photo by Matt King/Getty Images)