Prince Philip, Duke of Edinburgh practicing his bicycle polo technique, Windsor Great Park, Berkshire, 1964. (Photo by Norman Potter/Daily Express/Hulton Archive/Getty Images)

Teens got their glad rags on as they hit the town in Newcastle city centre, United Kingdom on August 16, 2018, as they celebrate their exam results. (Photo by North News and Pictures/NNP)

A member of the Pakistani Anti-Narcotic Force (ANF) takes a selfie beside a pile of burning drugs and liquor during a ceremony at the Kacha Ghari army firing range, on the outskirts of Peshawar on October 16, 2018, after the contraband was seized in raids across the province. (Photo by Abdul Majeed/AFP Photo)

The secretive indri (Indri indri) of Madagascar, the largest living lemur. It is also critically endangered and highly evolutionarily distinct with no close relatives, which makes its branch one of most precarious on the mammal evolutionary tree. In the likely event that the indri goes extinct, we will lose 19m years of unique evolutionary history from the mammal tree of life. (Photo by Pierre-Yves Babelon/Aarhus University)

A sandstorm hits the city of Zhangye in Gansu province, China on November 27, 2018. (Photo by Reuters/China Stringer Network)

With her husband, Brazil's new President Jair Bolsonaro in the background, Brazil's new first lady Michelle Bolsonaro gives a military salute from the Planalto Presidential palace, in Brasilia, Brazil, Tuesday, January 1, 2019. (Photo by Silvia Izquierdo/AP Photo)

People perform Chinese Lion dance in Chinatown during the Chinese Lunar New Year in Lima, Peru on February 5, 2019. (Photo by Guadalupe Pardo/Reuters)

Mackenzie Brown from the USA warms up on stage prior the final ofthe 47th Prix de Lausanne in Lausanne, Switzerland, 09 February 2019. Launched in 1973, the Prix de Lausanne is an international dance competition for young dancers. The best dancers will be awarded with scholarships granting free tuition in a world-renowned dance school or dance company. (Photo by Valentin Flauraud/EPA/EFE)