A visitor takes in a view of the downtown district from Twin Peaks on Friday, January 9, 2015, in San Francisco. (Photo by Marcio Jose Sanchez/AP Photo)

Snow covers roofs, streets and the Charles River following a winter blizzard in Boston, Massachusetts January 28, 2015. A powerful blizzard struck Boston and surrounding New England on Tuesday, leaving some 4.5 million people grappling with as much as three feet of snow and coastal flooding. (Photo by Brian Snyder/Reuters)

In this Tuesday, March 17, 2015 photo, a French military plane takes off from the flight deck of the French Navy aircraft carrier Charles de Gaulle in the Persian Gulf. Aircraft aboard the French carrier are flying bombing and reconnaissance missions as part of a U.S.-led coalition targeting Islamic State militants in Iraq. (Photo by Hasan Jamali/AP Photo)

U.S. Air Force wounded warrior, Capt. Sarah Evans, jumps rope in a gym in San Antonio, Texas. Evans was diagnosed with cancer while deployed to Afghanistan and was medically evacuated back to the United States where her leg was amputated. (Photo by Master Sgt. Jeffrey Allen/U.S. Air Force)

A building burns after an explosion on 2nd Avenue on March 26, 2015 in New York City. The seven alarm fire drew firefighters from across the city. A number of injuries have been reported. (Photo by Andrew Burton/Getty Images)

School girls stand next to a ballot box at a polling station during the municipal elections in Havana April 19, 2015. Cuba held its first local elections since a historic thaw in relations with the United States with an unusual wrinkle in the single-party system: two of the 27,000 candidates openly oppose the government. (Photo by Reuters/Stringer)

A supporter of Republican U.S. presidential candidate Donald Trump dresses in a Trump costume at a rally with supporters in Albuquerque, New Mexico, U.S., May 24, 2016. (Photo by Jonathan Ernst/Reuters)

A sniper of the French “Brigade d'Intervention” takes up his position at the top of the Arc de Triomphe during the annual Bastille Day military parade on the Champs-Elysees avenue in Paris on July 14, 2016. France holds annual Bastille Day military parade with troops from Australia and New Zealand as special guests among the 3,000 soldiers who will march up the Champs Elysees avenue. They will be accompanied by 200 vehicles with 85 aircraft flying overhead. (Photo by Stephane De Sakutin/AFP Photo)