A woman waits at a polio immunisation health centre, in Maiduguri, Borno State, Nigeria, August 29, 2016. Nigeria's military has liberated large swathes of land from Boko Haram but a ride with an army convoy, all guns firing for fear of ambush, shows how far the northeast is from normality after a brutal Islamist insurgency that has displaced millions. (Photo by Afolabi Sotunde/Reuters)

Racegoers in attendance on Ladies Day at Ascot Racecourse on June 21, 2018 in Ascot, England. Ladies Day is the biggest day in the racing calendar and brings with it all the glitz and glamour as those attending don their best outfits. Ascot Racecourse is steeped in Royal history, first founded by Queen Anne in 1711, with the first race in her honour held on August 11, 1711. This year’s Royal Ascot began Tuesday, June 19, with races every day until Saturday, June 23. (Photo by South West News Service)

Katie Rose Hobbs and Kirsten Elizabeth Pobjoy of British Aerosuperbatics Wingwalking Team perform ballet in the air during Huangguoshu Waterfalls Flight Conference on August 3, 2018 in Anshun, Guizhou Province of China. Huangguoshu Waterfalls Flight Conference including 18 aircraft from seven aerobatic teams from all over the world kicked off on Friday. (Photo by VCG via Getty Images)

Armenian police officers detain a protestor during an opposition rally in the Freedom Square in Yerevan, Armenia, 12 November 2020. Protesters demanded the resignation of Armenian Prime Minister Nikol Pashinyan and his government. The unrest and protest erupted in Yerevan on 10 November 2020 after Armenian Prime Minister and Presidents of Azerbaijan and Russia signed a trilateral statement announcing the halt of ceasefire and all military operations in the Nagorno-Karabakh conflict zone. (Photo by Stepan Poghosyan/EPA/EFE)

Men wear masks as they sit in the metro in Prague, Czech Republic, 17 March 2020. According to media reports, the Czech government decided to impose a two-week quarantine in the country on the evening of 15 March, and ban all international travel from 16 March 2020. Currently 383 cases of the coronavirus SARS-CoV-2, which causes the Covid-19 disease, have been officially confirmed in Czech Republic. (Photo by Martin Divisek/EPA/EFE)

In this Thursday, May 8, 2014 photo, Iranian coal miners push metal carts to be loaded with coal at a mine near the city of Zirab 212 kilometers (132 miles) northeast of the capital Tehran, on a mountain in Mazandaran province, Iran. International sanctions linked to the decade-long dispute over Iran's nuclear program have hindered the import of heavy machinery and modern technology in all sectors, and coal mining is no exception. (Photo by Ebrahim Noroozi/AP Photo)

A boy crawls under a cow during a religious ceremony celebrating the Tihar festival, also called Diwali, in Kathmandu, October 23, 2014. Hindus all over Nepal are celebrating the festival during which they worship cows, which are considered a maternal figure, and other animals. Also known as the festival of lights, devotees worship the goddess of wealth Laxmi by illuminating and decorating their homes using garlands, oil lamps, candles and colourful light bulbs. (Photo by Navesh Chitrakar/Reuters)

Parent hedgehogs Maria, left, and Gosha, 2nd right, eat with their albino babies in a private Zoo in Moscow, Russia, Thursday, August 22, 2013. Three rare albino hedgehog babies, born on the same day as Britain's new prince, have moved into a miniature castle at a Moscow petting zoo. The three are named after the Prince of Cambridge – George, Alexander and Louis. On Thursday, when they turned one month old, they were shown their new home at the All-Russia Exhibition Center. (Photo by Alexander Zemlianichenko Jr./AP Photo)