Bosnian men urge their horses to pull logs up a hill during a competition in the Bosnian town of Sokolac 50 kms west of Sarajevo, Bosnia,on Monday, April, 13, 2015. The annual festival celebrates the centuries old tradition of pulling logs honoring the owners of the strongest horses. Owners of the horses gather from all over Bosnia and beyond, and compete in a show of horse strength. (Photo by Amel Emric/AP Photo)

This artist image released from Japan's airline All Nippon Airways (ANA) on April 17, 2015 shows ANA's Boeing 787-9 aircraft into the colors of R2-D2 robot of Star Wars. Japanese air carrier ANA will place the special colored jetliner in service in this autumn. (Photo by AFP Photo/All Nippon Airways)

The feet of a Filipino penitent is nailed to a wooden cross during Good Friday rituals on April 3, 2015 at Cutud, Pampanga province, northern Philippines. Several Filipino devotees had themselves nailed to crosses Friday to remember Jesus Christ's suffering and death, an annual rite frowned upon by church leaders in this predominantly Roman Catholic country. (Photo by Aaron Favila/AP Photo)

A solar-powered plane takes off from Jiangbei International Airport in southwest China's Chongqing Municipality, Tuesday, April 21, 2015. The Solar Impulse 2 departed Chongqing on Tuesday for a 1190-kilometer (642-mile) flight to the city of Nanjing in eastern China, the sixth leg of its around-the-world flight. (Photo by Chinatopix via AP Photo)

A woman carrying a bundle on her head wait in line to cross the border into Colombia through the Simon Bolivar bridge in San Antonio del Tachira, Venezuela, Sunday, July 17, 2016. Tens of thousands of Venezuelans crossed the border into Colombia on Sunday to hunt for food and medicine that are in short supply at home. It's the second weekend in a row that Venezuela’s government has opened the long-closed border connecting Venezuela to Colombia. (Photo by Ariana Cubillos/AP Photo)

People help a dancer as he falls on stilts in honor of Saint Mary Magdalene in a street for the traditional “Danza de Los Zancos” (Los Zancos Dance), in the small town of Anguiano, northern Spain, Saturday, July 23, 2016. As an ancient tradition for more than 4th centuries, eight young people from the town balance on stilts down the old street, turning to the sound of folk music played on a pipe and drum. (Photo by Alvaro Barrientos/AP Photo)

A hillside erupts in flame as a raging wildfire fire burns in Placerita Canyon in Santa Clarita, Calif., Monday, July 25, 2016. A raging wildfire that forced thousands from their homes on the edge of Los Angeles continued to burn out of control Monday as frustrated fire officials said residents reluctant to heed evacuation orders made conditions more dangerous and destructive for their neighbors. (Photo by Nick Ut/AP Photo)

Russia's Darya Klishina prepares for the women's long jump qualification during the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Tuesday, August 16, 2016. She might be feeling the pressure of being all alone, but Darya Klishina could yet still win Russia's only athletics medal at the Rio 2016 Games. (Photo by Matt Dunham/AP Photo)