A demonstrator shows her arm with the name “Marielle” written on it, as she performs during a protest against the murder of councilwoman Marielle Franco in Rio de Janeiro, Brazil, Tuesday, March 20, 2018. Franco's murder came just a month after the government put the military in charge of security in Rio, which is experiencing a sharp spike in violence less than two years after hosting the 2016 Summer Olympics. (Photo by Leo Correa/AP Photo)

An Afghan boy jumps off the turret of a Soviet tank on a hilltop on the the outskirts of Kabul, Sunday, March, 4, 2018. (Photo by Rahmat Gul/AP Photo)

Kerry Katona (L) seen attending OK! Magazine's 25th anniversary party at The View from the Shard on March 21, 2018 in London, England. (Photo by Splash News and Pictures)

South Vietnamese forces escort suspected Viet Cong officer Nguyen Van Lem (also known as Bay Lop) on a Saigon street February 1, 1968, early in the Tet Offensive. Moments later, Lem was executed by Gen. Nguyen Ngoc Loan, chief of the national police. (Photo by Eddie Adams/AP Photo)

Women practice yoga during a performance on a glass bridge at the Shiniuzhai National Geo-park in Pingjiang county, Hunan province, China, November 5, 2015. About hundred yoga fans put on the show to promote the concept of green life and the idea of harmony between human and nature on Thursday, according to local media. (Photo by Reuters/China Daily)

A storm whips through a tented area occupied by Nepalese earthquake survivors as a mother grabs her infant child and runs to find shelter in Kathmandu, Nepal 23 May 2015. Nepalese, who lost their homes in earthquake and fear aftershocks, have been living in temporary shelter in open ground which they had to flee because of the heavy rain and powerful wind. (Photo by Narendra Shrestha/EPA)

A woman receives a bouquet made of vegetables and flowers, priced at 238RMB, from a delivery staff of a florist outside an office building on Valentine's Day in Beijing, China, February 14, 2017. (Photo by Jason Lee/Reuters)

A dog, at the behest of his owner, rides a skatebaord on April 3, 2017 in Berlin, Germany. The dog's owner, who looked like he might be homeless, coaxed the dog to ride the skatebaord and asked passersby who stopped to watch for money. (Photo by Sean Gallup/Getty Images)