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)

A local farmer Theophilus Mwendwa runs through a swarm of desert locusts to chase them away in the bush near Enziu, Kitui County, some 200km east of the capital Nairobi, Kenya, 24 January 2020. Large swarms of desert locusts have been invading Kenya for weeks, after having infested some 70 thousand hectares of land in Somalia which the United Nations Food and Agriculture Organisation (FAO) has termed the “worst situation in 25 years” in the Horn of Africa. FAO cautioned that it poses an “unprecedented threat” to food security and livelihoods in the region. (Photo by Dai Kurokawa/EPA/EFE)

A model presents a creation by Indian designer Amit Aggarwal during the grand finale of the Lakme Fashion Week (LFW) Summer/Resort 2020 in​ Mumbai, India, 16 February 2020. (Photo by Divyakant Solanki/EPA/EFE)

Border Security Force (BSF) soldiers ride their camels as they take part in a rehearsal for a road show ahead of the visit of U.S. President Donald Trump, in Ahmedabad, India, February 21, 2020. (Photo by Amit Dave/Reuters)

People mourn next to the body of Muddasir Khan, who was wounded on Tuesday in a clash between people demonstrating for and against a new citizenship law, after he succumbed to his injuries, in a riot affected area in New Delhi, February 27, 2020. (Photo by Adnan Abidi/Reuters)

People look at a black bear at the Chengdu zoo amid the coronavirus outbreak on March 26, 2020 in Chengdu, Sichuan Province of China. (Photo by Wang Lei/China News Service via Getty Images)

Police officers wield their batons against a man as a punishment for breaking the lockdown rules after India ordered a 21-day nationwide lockdown to limit the spread of coronavirus in New Delhi, India, March 25, 2020. (Photo by Adnan Abidi/Reuters)