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 Northern Lights glow green in a spectacular light show above a field of trees frozen solid with snow. (Photo by Jaak Sarv/Solent News & Photo Agency)

White lioness Azira lies in the cage with her three white cubs, on February 4, 2014. Zoo owner Andrzej Pabich says white lions often have defects that prevent giving birth, or the mother rejects her cubs, but Azira has been patiently feeding and caring for her little ones. (Photo by Czarek Sokolowski/Associated Press)

A woman covers her face as a fire burns in the middle of town during an anti-G20 protest on July 7, 2017 in Hamburg, Germany. Authorities are braced for large-scale and disruptive protests as Leaders of the G20 group of nations arrive in Hamburg for the July 7-8 G20 summit. (Photo by Leon Neal/Getty Images)

Sri Lankan military personnel march during the country's 66th Independence Day celebrations in the central town of Kegalle, about 40 kms from the capital Colombo on February 4, 2014. Sri Lanka cemmemorates its independence from British rule on February 4, 1948. (Photo by Ishara S. Kodikara/AFP Photo)

A woman crowd-surfs in front of the main stage at the Woodstock Festival in Kostrzyn-upon-Odra, close to the Polish-German border, August 2, 2014. Some 500 thousand people attended the festival that is the brainchild of Polish journalist and social campaigner Jerzy Owsiak. He initiated the event to say thank you to those who donated money to his GOCC charity organisation that delivers medical care for children. (Photo by Thomas Peter/Reuters)

A baby giant panda plays at Chengdu Research Base of Giant Panda Breeding in Chengdu, Sichuan province, China, January 22, 2017. (Photo by Jason Lee/Reuters)