The new Citroen Concept Car Divine DS is presented at the 2014 Paris Auto Show on October 2, 2014 in Paris on the first of the two press days. European carmakers are hoping to impress with new models at this week's Paris Motor Show and prove they have come out stronger from years of economic trouble and cost-cutting. (Photo by Miguel Medina/AFP Photo)

Two robotic legged squad support system (LS3) machines by the Defense Advanced Research Project Agency follow a technician during a demonstration at Joint Base Myer-Henderson Hall, Virginia, on September 10, 2012. (U.S. Marine Corps photo by Sgt. Mallory S. VanderSchans via The Atlantic)

Silver medalist Vivian Jepkemoi Cheruiyot of Kenya and gold medalist Almaz Ayana (R) of Ethiopia during the medal ceremony for the women's 10000m final of the Rio 2016 Olympic Games Athletics, Track and Field events at the Olympic Stadium in Rio de Janeiro, Brazil, 12 August 2016. (Photo by Sergei Ilnitsky/EPA)

Andrea Rossato, Italy. Professional; Candid. Children enjoy the simple pleasures of a seaside holiday. (Photo by Andrea Rossato/Sony World Photography Awards)

A photograph of Cuba's former President Fidel Castro decorates a wall inside a state-run market in Havana, March 8, 2016. (Photo by Alexandre Meneghini/Reuters)

Students walk to school on the first day of their new school year in Giza, south of Cairo, Egypt September 25, 2016. (Photo by Mohamed Abd El Ghany/Reuters)

Deshauna Barber (C) of the District of Columbia poses with other contestants after being crowned Miss USA 2016 during the 2016 Miss USA pageant at the T-Mobile Arena in Las Vegas, Nevada, U.S., June 5, 2016. (Photo by Steve Marcus/Reuters)

The sun streaks through the fall foliage at sunrise along the Potomac River in Arlington, Va., Wednesday, November 4, 2015 on a warm fall day in the nation's Capitol area. (Photo by J. David Ake/AP Photo)