A Fulani Pastoralist carries two baby sheep on her donkey cart as her family move on northwards in Barkedji, Senegal on July 21, 2020. Thousands of Pastoralist families will start the movement north in the next weeks. With the first rains comes fresh grass and water for the Fulani herders' livestock, it also marks the point where most of the Pastoralist will move northwards until the dry season. (Photo by John Wessels/AFP Photo)

A reveller of the Salgueiro samba school performs during the second night of Rio's Carnival at the Sambadrome in Rio de Janeiro, Brazil, on February 13, 2018. (Photo by Mauro Pimentel/AFP Photo)

A reveller from Salgueiro performs during the second night of the Carnival parade at the Sambadrome in Rio de Janeiro, Brazil on February 13, 2018. (Photo by Sergio Moraes/Reuters)

Soldier boys at Fort Dix, N.J., learn something about guns during their working hours, as they show their girlfriends at a camp dance, December 13, 1940. In front row, playing with the coin amusement gun, from left: Pvt. Tom D'Amato of West Orange; Rose Sinkewicz, behind gun site, of Trenton; Julia Ivans of Trenton, and Pvt. Vernon Landers of Kearney. Back row: Pvts. William Sargent and William Corlies of Philadelphia. (Photo by AP Photo)

British theoretical physicist Stephen Hawking, Cambridge University Professor and Fellow, circa 1985. Stephen Hawking, the brightest star in the firmament of science, whose insights shaped modern cosmology and inspired global audiences in the millions, has died aged 76. (Photo by Gemma Levine/Getty Images)

Models present creation for the 7th Hosa Cup China Swimwear Design contest and Hosa Swimwear Trend fashion show on day five of China Fashion Week A/W 2011 on March 28, 2011 in Beijing, China (Photo by Feng Li/Getty Images)

Models pose backstage ahead of the Gary Bigeni show during Rosemount Australian Fashion Week Spring/Summer 2011/12 at Overseas Passenger Terminal on May 4, 2011 in Sydney, Australia. (Photo by Matt King/Getty Images)

A dejected German Grenadier carrying a machine gun on his shoulder in front of a building on fire during the German retreat in Russia. (Photo by Keystone/Getty Images). 1944