Elephant Maja of Circus Bush on his daily walk with Circus ringmaster Hardy Scholl (R) on Berlin streets in Berlin, Germany June 30, 2016. (Photo by Stefanie Loos/Reuters)

Prince Philip, Duke of Edinburgh practicing his bicycle polo technique, Windsor Great Park, Berkshire, 1964. (Photo by Norman Potter/Daily Express/Hulton Archive/Getty Images)

Girls, who are part of Afghan Mobile Mini Circus for Children (MMCC), participate in a juggling competition in Kabul, Afghanistan August 12, 2015. The MMCC, founded by David Mason from Denmark, teaches cooperation and creativity to children scarred by years of war in Afghanistan. Despite the dangers, the project has grown so popular that it now runs centres in ten provinces and has hundreds of regular students. The circus makes visits to internally displaced persons' camps, schools, orphanages, and holds annual festivals. The children are taught the skills of juggling clubs, walking on stilts and acrobatics. (Photo by Ahmad Masood/Reuters)

An Afghan street vendor carries bread on his head ahead of the upcoming holy fasting month of Ramadan in Kabul, Afghanistan, Sunday, June 5, 2016. Muslims across the world will be observing the holy fasting month of Ramadan, when they refrain from eating, drinking and smoking from dawn to dusk. (Photo by Rahmat Gul/AP Photo)

An officer of the Afghan border police throws an assault rifle to a policeman participating in a military exercise on the outskirts of Herat, Afghanistan, Monday, September 7, 2015. Twelve female and seventy male border police personnel participated in the military exercise near the border with Iran in Herat province. (Photo by Hoshang Hashimi/AP Photo)

Sgt. William Olas Bee, a U.S. Marine from the 24th Marine Expeditionary Unit, has a close call after Taliban fighters opened fire near Garmsir in Helmand Province of Afghanistan, May 18, 2008. (Photo by Goran Tomasevic/Reuters)

An Afghan journalist takes a “selfie” as U.S. President Barack Obama (R) holds a joint news conference with Afghanistan's President Ashraf Ghani (C) at the White House in Washington March 24, 2015. (Photo by Jonathan Ernst/Reuters)

An Afghan policeman stands guard in front of a French restaurant “Le Jardin” after a suicide attack in Kabul, Afghanistan January 2, 2016. A suicide attack on a French restaurant in the Afghan capital Kabul on Friday killed a 12-year-old boy and wounded more than a dozen other people, officials said. (Photo by Mohammad Ismail/Reuters)