In this Sunday, June 27, 2010 file photo two men compete in an ostrich race at Highgate ostrich farm in Oudtshoorn, South Africa. Clambering onto an ostrich for a ride used to be popular among tourists in a South African town of Oudtshoorn known of as the “ostrich capital of the world”. Not so much anymore. Two major ostrich farms in Oudtshoorn have stopped offering ostrich rides to tourists, responding to concerns about the birds’ welfare. A third farm is sticking with the feature, saying it is regulated and that ostriches do not experience discomfort. The Highgate farm, however, continues to offer ostrich rides. (Photo by Shuji Kajiyama/AP Photo)

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)

A truck creates a wake as its driver tries to navigate a severely flooded street as heavy rains pour down Monday, September 8, 2014, in Phoenix. Storms that flooded several Phoenix-area freeways and numerous local streets during the Monday morning commute set an all-time record for rainfall in Phoenix in a single day. (Photo by Ross D. Franklin/AP Photo)

Mount Sinabung volcano erupts, as seen from Tiga Pancur village, Karo Regency in Indonesia's North Sumatra province, in this October 8, 2014 file photo. (Photo by Y. T. Haryono/Reuters)

Lazar and his sister Andjelka sit by a candle in their home in the eastern Serbian town of Majdanpek, December 4, 2014. Electricity workers in Serbia struggled through snow, ice and treacherous terrain on Thursday to restore electricity to an eastern town left shivering without power, heating or running water for a fourth day. (Photo by Marko Djurica/Reuters)

Russian cadet preparing before the International Kremlin Cadet Ball in Moscow, Russia 12 December 2017. More than 1500 students from all Russian cadets school attend in Cadet Ball. (Photo by Yuri Kochetkov/EPA/EFE)

Residents wade through flood waters from Tropical Storm Harvey in Beaumont Place, Houston, Texas on August 28, 2017. Houston was still largely paralyzed Monday, and there was no relief in sight from the storm that spun into Texas as a Category 4 hurricane, then parked itself over the Gulf Coast. (Photo by Jonathan Bachman/Reuters)

In this September 27, 2017 file photo, girls walk past a wall riddled with bullet holes from shootings between rival drug traffickers, at the Rocinha slum, in Rio de Janeiro, Brazil. Violence is on the rise in Rio's slums after several years of decline, and the killings of kids have shocked even residents long inured to deaths from gangs and police. (Photo by Silvia Izquierdo/AP Photo)