Two F-15E Strike Eagles wait to receive fuel from a KC-135R Stratotanker during exercise Red Flag 15-1 on their way to Nellis Air Force Base, Nev., Jauary 23, 2015. The F-15s are assigned to the 4th Fighter Wing. U.S. (Photo by Airman 1st Class Aaron J. Jenne/Reuters)

Afghanistan's interior ministry special forces demonstrate their skills during a military exercise in Kabul, Afghanistan, Thursday, April 2, 2015. Afghanistan's security forces took over full responsibility for the country's security on January 1, 2015. (Photo by Massoud Hossaini/AP Photo)

A girl looks out from the window of a “La Sabana” tourist train in La Caro March 1, 2015. The “La Sabana” tourist train that runs through the capital was founded by Eduardo Rodriguez, a railway engineer. Rodriguez has worked on Colombia's railway system his whole life and now, with an air of nostalgia, transports thousands of tourists in renovated steam locomotives that he fixes in Bogota's Central Station which dates back to 1913. (Photo by Jose Miguel Gomez/Reuters)

Oded Balilty is an Israeli documentary photographer. He is an Associated Press photographer and won the Pulitzer Prize for Breaking News Photography in 2007. Photo: A Jewish settler struggles with an Israeli security officer during clashes that erupted as authorities evacuated the West Bank settlement outpost of Amona, east of the Palestinian town of Ramallah, in this February 1, 2006, file photo. (Photo by Oded Balilty/AP Photo)

This photo taken on February 1, 2018 shows a worker trimming the skin imperfections of a silicone doll at a factory of EXDOLL, a firm based in the northeastern Chinese port city of Dalian. With China facing a massive gender gap and a greying population, a company wants to hook up lonely men and retirees with a new kind of companion: “Smart” sеx dolls that can talk, play music and turn on dishwashers. (Photo by Fred Dufour/AFP Photo)

Carlos Martinez (L), a representative of the Guinness World Records, examines the cooking process of a chocolate coin during an attempt to break the Guinness World Record for the biggest chocolate coin in Caracas, Venezuela, October 1, 2015. More than 80 people will work with 100% Venezuelan cacao to create the coin that is estimated to weigh 1,000 kg, according to local media. (Photo by Carlos Garcia Rawlins/Reuters)

People stand in the middle of the graves and in front of giant kites in the cemetery of Santiago Sacatepequez, Guatemala, November 1, 2015. Dating back 116 years, the tradition of flying kites in the cemetery of of Santiago Sacatepequez, integrates the Catholic feast of All Saints with ancient Mayan practices of honouring the dead. It is believed that the kites connect the living and the dead during the all saints day celebration. (Photo by Jorge Dan Lopez/Reuters)

Brides-to-be participate in the "Running of the Brides" race in a park in Bangkok November 28, 2015. A hundred husbands and wives-to-be wore their wedding dresses and running shoes and competed in an event for a combined prize worth 1 million Thai baht ($27,928), according to the organisers. (Photo by Athit Perawongmetha/Reuters)