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)

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)

Kurdish pesh merga troops fire at Islamic State positions as they move toward the Iraqi town of Badana Pichwk on Monday morning, October 17, 2016. Kurdish forces began Monday advancing on a string of villages east of Mosul, the start of a long-awaited campaign to reclaim Iraq's second-largest city from the Islamic State, which seized it more than two years ago, officials said. (Photo by Bryan Denton/The New York Times)

A girl holds her brother in her arm as black smoke rises after an oil well set on fire in the center of al-Kayyara town to the south of Daesh terror organization-held Mosul in Iraq on October 25, 2016. The oil well in the center of al-Kayyara town, which was set alight by retreating Daesh militants in advance of the Iraqi army's takeover of the town on August 24, 2016 has still not entirely been put out. The raw petrol which is still alight is creating black clouds above the city. The residents and wildlife beneath this polluting smoke cloud may find their health at risk. The effects of the fire in the town center on unprotected civilians' health can easily be seen on the hands and faces of children playing on the street. (Photo by dris Okuducu/Anadolu Agency/Getty Images)

Iraqi firefighters try to stop the fire of burning oil wells in Kirkuk, northern Iraq, 02 June 2016. Two Khabbaz oil field wells in Kirkuk Province, northern Iraq, exploded by suspected insurgents, a security official said. (Photo by EPA/Stringer)

Eagle Prime (MK3), a giant robot by MegaBots Inc. which manufactures giant piloted humanoid fighting robots headquartered in Berkeley, California on October 18, 2017. (Photo by Courtesy Michael Mauldin/Reuters/MegaBots Inc)

A US Marine leads two Viet Cong suspects in restraints during the Tet Offensive on February 20, 1967. (Photo by Bettmann Archive/Getty Images)

Rowers enter in Canaregio river during the 42nd Venice Vogalonga on May 15, 2016 in Venice, Italy. 42 years ago a group of Venetians, both amateur and professional rowers, came up with an idea of non-competitive race in which any kind of rowing boat can take part. The first Vogalonga began with the message to protest against the growing use of powerboats in Venice and the swell damage they do to the historic city. (Photo by Awakening/Getty Images)