People on motor bikes celebrate American President Barack Obama's visit to Kenya by holding up a photo, center top, of the president and First Lady Michelle Obama in Kisumu, Kenya, Saturday, July 25, 2015. President Barack Obama heralded Africa as a continent “on the move” Saturday as he opened a U.S.-sponsored business summit in Kenya, the East African nation where he has deep family ties. (Photo by AP Photo)

Brazilian navy soldiers watch a woman as they patrol the area at the Copacabana Beach before carnival festivities in Rio de Janeiro, Brazil February 14, 2017. (Photo by Sergio Moraes/Reuters)

Festival goer practice yoga during the O.Z.O.R.A. festival on August 4, 2016 in Tolna, Hungary. Ozora is a village in Tolna County. In recent times it has become famous for the O.Z.O.R.A. psychedelic trance festival which has been held on an estate in Ozora near small village Dadpuszta every year since 2004. The first party was called Solipse and took place during the Solar eclipse of August 11, 1999. (Photo by Mohai Balázs/MTI/MTVA)

Principle Ballet Dancer, Ekaterina Bulgutova, of the Russian State Ballet, with the Nutcracker part of Christmas Ballet Season in Cardiff which starts at St Davids Hall on December 20, 2016 in Cardiff, England. (Photo by Kiran Ridley/Barcroft Images)

A dramatic sunset acts as a backdrop to Stonehenge on November 20, 2008 in Stonehenge, England. (Photo by Mike Hewitt/Getty Images)

An Egyptian security guard screams at people as medics bring in a stretcher to carry the wounded after the attack which killed President Anwar Sadat, October 6, 1981, as he watched a military parade. (Photo by AP Photo)

A Palestinian throws snow at his wife during a snow storm in West Bank old city of Hebron, January 26, 2016. (Photo by Mussa Qawasma/Reuters)

A PETA (People for the Ethical Treatment of Animals) activist with her body painted promotes veganism in Bangkok April 21, 2016. (Photo by Jorge Silva/Reuters)