An Indian Hindu devotee celebrates Holi, the spring festival of colours, during a traditional gathering at a temple in Nandgaon village in Uttar Pradesh state on March 16, 2019. Holi, the popular Hindu spring festival of colours is observed in India at the end of the winter season on the last full moon of the lunar month. (Photo by Noemi Cassanelli/AFP Photo)

Chinese aids activists hand out condoms in a subway train in Wuhan, central China's Hubei province on December 1, 2014. The World Health Organization issued a call to action to China on December 1, 2014 over HIV/AIDS as government figures said nearly half a million people are living with the disease or its precursor, with hundreds of thousands more thought to be undiagnosed. (Photo by AFP Photo)

Couples take part in the “Love and Challenge Marathon” in Hanoi, Vietnam, 16 August 2015. Fifty couples, who are going to get married, participated in the event which is held the fifth time. This year, the winners of the marathon received a honeymoon trip to Malaysia. (Photo by Luong Thai Linh/EPA)

Competitors take part in the 8th annual World Gravy Wrestling Championships at the Rose n Bowl Pub in Bacup, north west England on August 31, 2015. Contestants must participate in fancy dress and wrestle in a pool of Lancashire Gravy for 2 minutes whilst being scored for a variety of wrestling moves. (Photo by Oli Scarff/AFP Photo)

Indian Air Force personnel parade during the 85th Air Force Day celebrations at Hindon Air Force base in Ghaziabad on October 8, 2017. (Photo by AFP Photo/Stringer)

Technical staff take shelter as a helicopter takes off prior to the Nendaz Freeride skiing and snowboard competition, a Freeride World Tour Qualifier (FWQ) event, on the Mont Gond in Nendaz, Switzerland on March 21, 2018. (Photo by Valentin Flauraud/EPA/EFE/Rex Features/Shutterstock)

The competition is run by Royal Observatory Greenwich sponsored by Insight Investment and in association with BBC Sky at Night Magazine. This year astrophotographers from 91 countries sent in more than 4,200 spectacular entries. Here: The Milky Way rises above an isolated lighthouse in Tasmania. Shot by James Stone of Australia. (Photo by James Stone/Astronomy Photographer of the Year 2018)

North Korea's Samjiyon Orchestra performs at Pyongyang Grand Theatre in Pyongyang, North Korea, September 18, 2018. (Photo by Pyeongyang Press Corps/Pool via Reuters)