In advance of Fleet Week performances, the U.S. Navy Blue Angels and Team Oracle aerobatics pilot Sean D. Tucker fly over the San Francisco Bay during a photo flight on Thursday, October 5, 2017. (Photo by Noah Berger/AP Photo)

A Kurdish girl wears her relative's assault rifle and ammunition belt as she waits at the Iraqi Kurdish Shaqouli checkpoint, some 35 kilometres east of Mosul, on November 10, 2016. Since the start of the Mosul offensive the Kurds have moved their border some 10 kms closer to Iraq's second city, marking it out with a line in the sand. (Photo by Odd Andersen/AFP Photo)

A Syrian refugee man (obscured) moves boxes of goods at his shop in Zaatari refugee camp near the border with Syria, in Mafraq, Jordan October 15, 2016. (Photo by Ammar Awad/Reuters)

A woman and her dogs stop and look at a store mannequin wearing a dog's head mask outside a fashion shop in Nice, France, May 3, 2016. (Photo by Eric Gaillard/Reuters)

A workman smooths out the gravel near the base of British artist Alex Chinneck' latest sculpture “A bullet from a shooting star” on the Greenwich Peninsula in London on September 17, 2015. The 35-metre tall, upside-down electricity pylon overlooks the Canary Wharf financial district. (Photo by Leon Neal/AFP Photo)

Winton Elementary fifth graders Juliana Ragan, from left, Chloe Windsor and Paisley Ganske wait backstage for their turn to perform as the Andrew Sisters during the Pearl Harbor/Veterans assembly at the school on Monday, December 7, 2015, in Coeur d'Alene, Idaho. Dec. 7 is the 74th anniversary of the Japanese bombing of Pearl Harbor. (Photo by Kathy Plonka/The Spokesman-Review via AP Photo)

Bus 392 stands on the highway running from Beersheva to Eilat, with windows broken following a gun attack on August 18, 2011 near the Israel - Egypt border, Israel. A series of coordinated gun and roadside bomb attacks against miltary and civilian targets near the Israeli - Egyptian border, including an ambush on the bus travellling 20km north of Eilat, are reported to have left 5 dead and many injured. (Photo by Yehuada Ben Itah/Getty Images)

A female soldier from the honour guards prepares for a welcoming ceremony for Uruguay's President Tabare Vazquez at the Great Hall of the People in Beijing, China, October 18, 2016. (Photo by Jason Lee/Reuters)