Romanian military doctors and medical students sit on a bus behind steamy windows before the National Day parade in Bucharest, Romania, Thursday, December 1, 2016. Military planes and helicopters flew over the Romanian capital Thursday as thousands turned out to celebrate the national day, marking the date when the country reunified with Transylvania in 1918. (Photo by Vadim Ghirda/AP Photo)

Smoke and flames rise over a warehouse storing ammunition for multiple rocket launcher systems at a military base in the town of Kalynivka in Vinnytsia region, Ukraine September 27, 2017. Ukrainian officials say they have evacuated more than 30,000 people after a fire and ammunition explosions, at the military base on Tuesday. (Photo by Gleb Garanich/Reuters)

Members of an Orthodox community take part in an Easter service at a church in the village of Poteryaevka, some 200 km (124 miles) southwest of the city of Barnaul in Russia's Altai region, on April 24, 2011. (Reuters/Andrei Kasprishin)

Clowns and entertainers gather to attend an annual service of remembrance in honour of British clown Joseph Grimaldi at All Saints Church in Haggerston in London, Britain, February 5, 2017. (Photo by Toby Melville/Reuters)

People wearing Christmas hats bath in a pool of watermelon peel during a Christmas service at a hot spring in Luoyang, Henan province, China, December 24, 2016. (Photo by Reuters/Stringer)

Tourists enjoy blooming cherry blossoms at China Pharmaceutical University on March 22, 2021 in Nanjing, Jiangsu Province of China. (Photo by Yang Bo/China News Service via Getty Images)

Nursing students attend a capping ceremony on May 10, 2021 in Jinan, Shandong Province of China. International Nurses Day is observed annually on May 12. (Photo by Zhang Yong/China News Service via Getty Images)

The Langdale Pikes in the Lake District in North West England are illuminated on September 14, 2020 by a team of 30 climbers to celebrate the 50th anniversary of the local mountain rescue service. (Photo by Tom Mcnally/Triangle News)