Syrian Internal Security Forces dance in celebration during their graduation ceremony, at Ain Issa desert base, in Raqqa province, northeast Syria, Thursday, July 20, 2017. Some 250 residents of Syria's Raqqa province are the latest batch to graduate from a brief U.S-training course that is preparing an internal security force to hold and secure areas as they are captured from Islamic State militants. (Photo by Hussein Malla/AP Photo)

Convicted murderer Hector Alvarado Mazariegos, right, drops to the ground as he is hit by bullets of a Guatemala firing squad in the public cemetery at Mazatenango, June 28, 1975. His companion, Rocael Ortiz, met the same fate a few seconds later. Both were convicted of murder. (Photo by AP Photo/Anzueto)

Singer Rihanna prepares for a photoshoot with photographer Annie Leibovitz in Havana, Cuba, May 28, 2015. (Photo by Reuters/Stringer)

In this photo taken late Thursday, May 7, 2015, a prison guard, left, and seated inmates cast shadows on a wall while waiting for the beginning of a rock concert by Romanian band Pro Musica, inside the Popa Sapca jail in Timisoara, western Romania. (Photo by Adi Piclisan/AP Photo)

Elementary school sumo wrestlers compete in the sumo ring during the Wanpaku sumo-wrestling tournament in Tokyo, Japan July 30, 2017. (Photo by Kim Kyung-Hoon/Reuters)

Four actors on horseback dressed in Game of Thrones related costumes carry the Queen's Baton as they make their way way along the Dark Hedges on August 29, 2017 in Antrim, Northern Ireland. The Dark Hedges near Stranocum in County Antrim featured as the King's Road in season two of Game of Thrones and has become a tourist mecca for fans of the television series along with other filming locations in the province. The Queen's Baton Relay is currently on a tour of the United Kingdom as it makes its way around Europe in preparation for the 2018 Commonwealth Games in Australia. (Photo by Charles McQuillan/Getty Images)

Former Playboy Bunny Angie Best prepares backstage ahead of her return as the iconic Bunny Mother exclusively at the Telling Tales event at Playboy Club London on September 21, 2017 in London, England. (Photo by Tim P. Whitby/Tim P. Whitby/Getty Images for Playboy)

Furniture design “Chair” by Allen Jones ( £600,000-800,000) is seen at Christie's London on September 29, 2017 in London, England. Christie's Auction House is to sell millions of pounds worth of art and design from the 20th and 21st centuries during Frieze Week from October 3rd to October 7th. (Photo by Nils Jorgensen/Rex Features/Shutterstock)