A wolf looks into the camera at the 30 km (19 miles) exclusion zone around the Chernobyl nuclear reactor in the abandoned village of Orevichi, Belarus, March 2, 2016. What happens to the environment when humans disappear? Thirty years after the Chernobyl nuclear disaster, booming populations of wolf, elk and other wildlife in the vast contaminated zone in Belarus and Ukraine provide a clue. (Photo by Vasily Fedosenko/Reuters)

Children wave Vietnamese and American flags while waiting for arrival of U.S. President Barack Obama (not pictured) before a welcoming ceremony at the Presidential Palace in Hanoi, Vietnam May 23, 2016. (Photo by Reuters/Kham)

An Indian soldier from the international peace keeping force (IPKF) instructs young Sri Lankan recruits in shooting, part of the training given to the citizen's volunteer force in the North-Eastern Sri Lankan city of Batticaloa, September 28, 1989. (Photo by Barbara Walton/AP Photo)

A villager dries chillies on September 1, 2020 in Bijie, Guizhou Province of China. (Photo by VCG/VCG via Getty Images)

Fallen leaves cover the undergrowth as a commuter on a bicycle makes her way through the Tiergarten park in central Berlin on December 7, 2020. (Photo by Odd Andersen/AFP Photo)

Santa Claus wears a mask as he pushes a sleigh full of curbside grocery orders to an Aldi customer at a parking lot in Palatine, Ill., Saturday, December 19, 2020. For this weekend only, Santa Claus is delivering groceries to Aldi customers in Palatine and several other towns in the Chicago area. (Photo by Nam Y. Huh/AP Photo)

A man stacks more bricks on his head while working at in brickfields Narayanganj near Dhaka, Bangladesh on January 02, 2021. (Photo by Kazi Salahuddin Razu/NurPhoto via Getty Images)

Visitors take photos of a child dressed in a traditional costume before a folk performance in Panyu, Guangdong province, China on April 20, 2018. (Photo by Reuters/China Daily)