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)

In this Friday, May 10, 2019, file photo, rescuers help a baby wild elephant cross the wetland to return to the forest at Deepor Beel wildlife sanctuary in Gauhati, India. The elephant had gotten stuck in the waters of Deepor Beel after it was separated from a herd of wild elephant that came down in search of food last night. (Photo by Anupam Nath/AP Photo)

Chinese artist Zhou Jie takes a nap on an unfinished iron wire bed, one of her sculpture works, after lunch as a friend of hers looks on at Beijing Now Art Gallery, in Beijing August 11, 2014. Zhou started her art project titled “36 Days” on August 9, in which she would live inside an exhibition hall with an unfinished iron wire bed, some iron wire sculptures in the shape of stuffed animal dolls, a certain amount of food and her mobile phone, for 36 days. The entire process is open to visitors and she may also interact with them, according to Zhou. (Photo by Jason Lee/Reuters)

Soviet Army soldiers sit on their tanks in front of the Czechoslovak Radio station building in central Prague during the first day of Soviet-led invasion to then Czechoslovakia on August 21, 1968. (Photo by Libor Hajsky/Reuters)

A Sikh warrior, wearing a huge turban attends the annual fair of “Hola Mohalla” in Anandpur Sahib, in the northern Indian state of Punjab, Monday, March 17, 2014. Believers from various parts of northern India collect at the religious fair to celebrate the festival of Holi in a tradition set by the tenth Sikh guru Guru Gobind Singh in the seventeenth century. Nihangs, or Sikh warriors, display their martial skills and attire during the fair, believed to be maintained in the exact tradition as set by the Guru. (Photo by Altaf Qadri/AP Photo)

Canada's Mandy Marchak (R) is taken down by France's Pauline Biscarat during the final match of the Hong Kong Sevens rugby women's invitational cup in Hong Kong March 28, 2014. (Photo by Tyrone Siu/Reuters)

Planes land in fog at Heathrow Airport, west London, as heavy fog covers a many parts of the south east, on April 1, 2014. (Photo by Steve Parsons/PA Wire)

Palestinian female Hamas security officers demonstrate their skills during a graduation ceremony in the northern Gaza Strip, Wednesday, April 2, 2014. 1200 officers graduated from advanced training courses that lasted one year in Gaza police academy of Hamas. (Photo by Adel Hana/AP Photo)