Ten-year-old Macy Friday, front left, reacts as she looks back at her family after meeting Hillary Clinton, front right, as she campaigns for U.S. Sen. Mark Udall, D-Colo., back, during a stop in the newly-renovated Union Station in Denver on Monday, October 13, 2014. Clinton appeared at an event to raise money for Udall's current re-election campaign and then headed to Las Vegas for another appearance on Monday night. (Photo by David Zalubowski/AP Photo)

Men stroll past roadside vendors as a painted truck makes its way through the busy street in Kabul, Afghanistan, November, 1961. (Photo by Henry S. Bradsher/AP Photo via The Atlantic)

“Asaro from the Eastern Highlands”. The mudmen could not cover their faces with mud because the people of Papua New Guinea thought that the mud from the Asaro river was poisonous. So instead of covering their faces with this alleged poison, they made masks from pebbles that they heated and water from the waterfall, with unusual designs such as long or very short ears either going down to the chin or sticking up at the top, long joined eyebrows attached to the top of the ears, horns and sideways mouths. (Photo and caption by Jimmy Nelson)

Members of the Al-Baraa bin Malek batallion, part of the Free Syria Army's Al-Fatah brigade, duck to the ground as they pull a man (R) who was shot by a sniper twice in the Bustan al-Basha district of the northern city of Aleppo on October 20, 2012. (Photo by Javier Manzano/AFP Photo)

Marco Antonio Eguchi of Brazil gets bucked off of Bottoms Up in the first round of the PBR Frontier Communications Iron Cowboy at AT& T Stadium on February 18, 2017 in Arlington, Texas. (Photo by Tom Pennington/Getty Images)

An injured Iraqi Emergency Response Division (ERD) soldier hit by a mortar is held by another officer as they wait for medics to arrive at the Islamic State occupied Mosul Airport in west Mosul, part of the offensive to retake the city some two years after it fell to the hardline jihadist group, February 23, 2017. Iraqi forces encountered stiff resistance with improvised explosives, heavy mortar fire and snipers hampering their advance before they successfully took the airport. (Photo by Martyn Aim/Getty Images)

Iraqis run for cover as they flee Mosul's Al-Tayaran neighbourhood on February 28, 2017, during an offensive by Iraqi forces to retake the area from Islamic State (IS) group fighters. Hundreds of civilians fled through the desert to escape fighting and privation in Mosul, joining thousands of others who left their homes as conditions worsen in the city's west. (Photo by Ahmad Al-Rubaye/AFP Photo)

A woman lies injured after an incident on Westminster Bridge in London on Wednesday, March 22, 2017. A police officer has been stabbed near to the British Parliament and the alleged assailant shot by armed police. Scotland Yard report they have been called to an incident on Westminster Bridge where several people have been injured by a car. (Photo by Toby Melville/Reuters)