A boy moves away as a United Nations World Food Programme (WFP) helicopter lands in Rubkuai village, Unity State, northern South Sudan, February 18, 2017. South Sudan on Monday declared famine in some parts of the country, with more than three years of war leaving nearly five million hungry in what aid groups called a “man-made” tragedy. (Photo by Siegfried Modola/Reuters)

Snow falls as a woman walks her dog in the village of Podolye, 70 kilometers (43 miles) east of St. Petersburg, Russia, early Thursday, May 11, 2017. North winds brought snow to the east of the St. Petersburg region. (Photo by Dmitri Lovetsky/AP Photo)

In this photo taken Saturday, September 23, 2017, a mouse is cooked on a fire after being caught in a cornfield in Chidza, Masvingo Province, Zimbabwe. Considered a delicacy, the field mice are hunted in cornfields where they have grown plump on the grains, grass and wild fruits. (Photo by Tsvangirayi Mukwazhi/AP Photo)

People in Kathmandu joke that the face mask has now become part of the national dress – an indispensable accessory in an effort to protect themselves from the dust. Nepal has the worst air quality in the world, according to the Environmental Performance Index. (Photo by Pete Pattisson/The Guardian)

Mariam Emad from Parkour Egypt “PKE” practices her parkour skills around buildings on the outskirts of Cairo, Egypt on July 20, 2018. A group of Egyptian women gather at an abandoned park in a Cairo suburb once a week, climbing walls and jumping around in the strenuous physical discipline known as Parkour, while also challenging the country's conservative social norms. (Photo by Amr Abdallah Dalsh/Reuters)

A couple sit on the terrase of a cafe in Istanbul as seagulls fly over them on September 10, 2019. (Photo by Ozan Kose/AFP Photo)

Tom Kaulitz and Heidi Klum attend Heidi Klum's 20th Annual Halloween Party presented by Amazon Prime Video and SVEDKA Vodka at Cathédrale New York on October 31, 2019 in New York City. (Photo by Craig Barritt/Getty Images for SVEDKA)

In this photo taken Friday, December 9, 2016, young ballerinas practice under the instruction of Kenyan ballet dancer Joel Kioko, 16, in a room at a school in the Kibera slum of Nairobi, Kenya. (Photo by Ben Curtis/AP Photo)