Vigilantes armed with automatic rifles patrol the streets of Bujumbura, a city plagued by killings and violence as Burundi's crisis deepens. Here: an armed vigilante holds an AK-47 rifle in the center Bujumbura, Burundi, November 20, 2015. (Photo by Goran Tomasevic/Reuters)

A motorcyclist dodges in the annual water-splashing festival to mark the New Year of the Dai minority in Menglian, Yunnan province April 13, 2015. (Photo by Wong Campion/Reuters)

Shaymaa Ismaa’eel, a 24-year-old Muslim woman passes by a group of angry protesters at an Islamic conference in Washington, DC on April 21, 2019. In response, she crouched in front of them and flashed a peace sign. The photo, posted on Instagram, prompted an outpouring of support. (Photo by Shaymaa Ismaa'eel/Instagram)

People visit the Antelope Valley California Poppy Reserve in Lancaster, California, to view the flowers blooming on April 6, 2023. California’s biologically diverse landscapes are home to more than 7,000 species of native plants, and the California Poppy, also known as golden poppy, a flowering plant native to the United States and Mexico became the official state flower in 1903. (Photo by Frederic J. Brown/AFP Photo)

A little girl seen waiting in a queue to participate in the Kumari Puja ritual in Kolkata, India on March 30, 2023. Kumari Puja is an Indian Hindu Tradition mainly celebrated during the Durga Puja / Basanti Puja / Navratri according to Hindu calendar. Kumari actually describes a young virgin girl from the age 1 to 16 who is getting worshipped during the transition of Ashtami / Navami tithi of Durga Puja / Navaratri according to Hindu mythology. (Photo by Avishek Das/SOPA Images/Rex Features/Shutterstock)

“A fter the former Soviet Union conducted its first nuclear test in August 1949, the US reevaluated its postwar defense policies. With the US monopoly on atomic weapons broken, military and political leaders chose to diversify the American stockpile by developing thermonuclear and tactical nuclear weapons. One of the more interesting concepts to come out of this period was atomic artillery, which was successfully tested at the Nevada Proving Grounds (now the Nevada Test Site) in May 1953”. – Alan Carr. Photo: Atomic Annie at work during the Upshot-Knothole test series, 1953. (Photo by Los Alamos National Laboratory/US Army)

The Northern Lights glow green in a spectacular light show above a field of trees frozen solid with snow. (Photo by Jaak Sarv/Solent News & Photo Agency)