Young gymnasts practice pull-up on a bar at a gymnasium of a sports school in Jiaxing, Zhejiang province April 11, 2015. (Photo by William Hong/Reuters)

Two robotic legged squad support system (LS3) machines by the Defense Advanced Research Project Agency follow a technician during a demonstration at Joint Base Myer-Henderson Hall, Virginia, on September 10, 2012. (U.S. Marine Corps photo by Sgt. Mallory S. VanderSchans via The Atlantic)

The new Citroen Concept Car Divine DS is presented at the 2014 Paris Auto Show on October 2, 2014 in Paris on the first of the two press days. European carmakers are hoping to impress with new models at this week's Paris Motor Show and prove they have come out stronger from years of economic trouble and cost-cutting. (Photo by Miguel Medina/AFP Photo)

An Afghan girl rides a horse at the beach in Karachi, Pakistan, 07 September 2020. (Photo by Rehan Khan/EPA/EFE)

Andreyka, a 10-month-old female bear cub, plays with Rommi, an Alaskan malamute, at the Siberian Zoo in the settlement of Listvyanka, Irkutsk Region, Russia on December 9, 2020. The bear cub, which was found in a weak condition earlier this year, now play-fights with the Alaskan malamute, who adopted her and has seen three generations of bear cubs brought up in the Siberian zoo and released back into the wild. (Photo by Yuri Novikov/Reuters)

A man treats a woman affected by pepper spray as Washington Metropolitan Police officers clash with demonstrators trying to pull down the statue of U.S. President Andrew Jackson in the middle of Lafayette Park in front of the White House during racial inequality protests in Washington, D.C., U.S., June 22, 2020. Dozens of law enforcement officers, led by U.S. Park Police, stormed into the square, swinging batons and firing chemical agents to scatter protesters. By dark, police had taken control and outnumbered demonstrators in the immediate area. (Photo by Tom Brenner/Reuters)

Carnival participants dressed in costume and wearing body paint pose for a group picture during the annual Zambo carnival held in Lebanon's northern city of Tripoli on March 14, 2021, marking the last period of excess on the eve of the Christian Greek Orthodox lent. The inspiration of the annual Zambo celebration is unclear, despite it being a tradition that stretches back over a century to when an emigrant to Brazil returned to his native Tripoli bringing the carnival with him. (Photo by Ibrahim Chalhoub/AFP Photo)

A Sadhu, Hindu holy person, prepares himself by smearing ashes on his body during the Maha Shivaratri festival at the Pashupati Temple in Kathmandu, Nepal, 11 March 2021. The Maha Shivratri festival, which is celebrated on 11 March, sees Hindu devotees, from across the country and neighboring India, gather to celebrate the birthday of Lord Shiva, the Hindu god of creation and destruction, by offering special prayers and fasting. (Photo by Narendra Shrestha/EPA/EFE)