An army dog stands up as retiring soldiers salute their guard post before retirement in Suqian, Jiangsu province, China on November 29, 2017. (Photo by Reuters/China Stringer Network)

In this picture taken on December 13, 2017, a woman commutes on a street on a cold day in Baoding. As temperatures dipped below freezing in a northern Chinese village, a group of parka-clad women tried to stay warm as they played mahjong around a small gas stove in a grocery store. (Photo by Fred Dufour/AFP Photo)

This picture taken on December 31, 2017 shows an Indian sadhu preparing food at a camp at Sangam, ahead of the Magh Mela festival, in Allahabad. The Magh Mela, which is known as a mini-Kumbh Mela, is scheduled to start January 2 and continue until February 13 with auspicious bathing dates throughout the 45 day period. (Photo by Sanjay Kanojia/AFP Photo)

A devotee looks at the camera as she offers prayers to the setting sun during the “Chhath” festival at Bagmati River in Kathmandu, Nepal on October 26, 2017. (Photo by Navesh Chitrakar/Reuters)

Antonina Yermokhina, 86, does physical exercises during her daily training session on the embankment of the Yenisei River in the Siberian town of Divnogorsk, Russia November 13, 2017. (Photo by Ilya Naymushin/Reuters)

Police officers display their AI-powered smart glasses in Luoyang, Henan province, China on April 4, 2018. (Photo by Reuters/China Stringer Network)

Blossoms and dust are blown by the wind as Jasmin Ricks, left, and her sister, Jessica Ricks, center, take in the cherry blossoms near the Tidal Basin in Washington on April 12, 2018. (Photo by Matt McClain/The Washington Post)

A man transports passengers on an improvised motorized rickshaw during heavy rains in Agartala, India, April 20, 2018. (Photo by Jayanta Dey/Reuters)