A dancer poses for her own photographer in front of pink cherry tree blossoms during a sunny spring morning at the Parc de Sceaux gardens near Paris, France, April 12, 2019. (Photo by Christian Hartmann/Reuters)

Sudanese fishermen check their boats and nets before they row through the waters of Nile River near Jebel Aulia, Sudan, May 3, 2019. (Photo by Umit Bektas/Reuters)

This Sunday, September 7, 2014 photo provided by Rachel Kirk shows smoke from a fire rising above Little Yosemite Valley near Yosemite National Park, Calif. (Photo by Rachel Kirk/AP Photo)

A hot air balloon floats past an almost full rising moon on a warm fall evening near Encinitas, California October 5, 2014. (Photo by Mike Blake/Reuters)

Pawel Karpinski and Nadine Kinczel of Poland dance as they compete during IPC Wheelchair Dance Sport European Championships in Lomianki near Warsaw, November 9, 2014. (Photo by Kacper Pempel/Reuters)

Migrating starlings fly in formation near the southern Israeli town of Rahat February 2, 2015. The phenomenon, known as murmuration, is most common during the winter months. (Photo by Nir Elias/Reuters)

A Ukrainian serviceman wearing a new year's hat waves at his comrades while standing beside his tank near Debaltseve, eastern Ukraine, February 8, 2015. (Photo by Gleb Garanich/Reuters)

North Korean children wave to people on a Chinese tourist boat on the banks of Yalu River near the Chongsong county of North Korea, opposite the Chinese border city of Dandong, May 8, 2011. (Photo by Jacky Chen/Reuters)