Stray dogs stand on tombs in Diamond Hill cemetery in Hong Kong, China, 04 April 2017. According to the lunar calendar, the Qingming Festival is observed on 04 April . The Qingming Festival, also known as Tomb-Sweeping Day, is marked by Chinese people by going to the cemetery to cleaning up tombs, bring flowers, and making offerings to their ancestors. (Photo by Jerome Favre/EPA)

Joseph Szabo was a frustrated high-school teacher in need of inspiration – so he started photographing his students, and captured all the angst and excitement of being caught between childhood and adulthood. Here: “Priscilla”, 1969. (Photo by Joseph Szabo/Courtesy of Michael Hoppen Gallery/The Guardian)

Seiichiro Nishimoto, CEO of Shelter Co., poses wearing a gas mask at a model room for the company's nuclear shelters in the basement of his house in Osaka, Japan on April 26, 2017. With nearby North Korea increasing its show of power day by day with missile launches and nuclear tests, people in Japan are preparing for the worst by building private nuclear shelters, Reuters reports. (Photo by Kim Kyung-Hoon/Reuters)

Wu Lingling, a nurse from Central Hospital of Shanghai Fengxian District says goodbye to her husband Zhao Kun before leaving for Wuhan at Shanghai South Railway Station in east China's Shanghai, January 27, 2020. A team comprised of 50 medical workers from 40 hospitals in Shanghai left for Wuhan City on Monday to aid the novel coronavirus control efforts there. (Photo by Ding Ting/Xinhua News AgencyAlamy Live News)

An unidentified man brandishes a gun during a protest against a new citizenship law outside the Jamia Millia Islamia University in New Delhi, India, January 30, 2020. The gunman went live on Facebook to warn he was taking his “final journey” before firing at the protest. (Photo by Danish Siddiqui/Reuters)

Victoria Sinitsina and Nikita Katsalapov of Russia perform during Gala exhibition skating program of the ISU European Figure Skating Championships in Graz, Austria, 26 January 2020. (Photo by Tatyana Zenkovich/EPA/EFE)

Aurora Borealis, or Northern Lights, shine over the plane wreck of a US Navy airplane – a Douglas Super DC-3 – on the Black Beach in Solheimasandur, south Iceland on January 18, 2018. (Photo by Owen Humphreys/PA Images via Getty Images)

Miguel Toribio, 11, puts a pistol belonging to his father into his belt, before demonstrating newly learnt skills from military-style weapons training, to a Reuters journalist in Ayahualtempa, Mexico, February 3, 2020. (Photo by Alexandre Meneghini/Reuters)