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)

Street musicians with their faces covered with animal masks play to earn some money in central Vienna, Austria, November 8, 2015. (Photo by Vasily Fedosenko/Reuters)

Residents of the Brussels suburb of Molenbeek are searched by police before taking part in a memorial gathering to honour the victims of the recent deadly Paris attacks, in Brussels, Belgium, November 18, 2015. (Photo by Yves Herman/Reuters)

A participant of “Bread Procession of the Saint”, takes part in the ceremony in honor of Domingo de La Calzada Saint (1019-1109) who helped poor people and pilgrimage, in Santo Domingo de La Calzada, northern Spain, Wednesday, May 11, 2016. Every year during spring season, “Las Doncellas” (White Virgins), hold on their head a basket cover with white cloth while they walk past along of this old village in honor of the saint. (Photo by Alvaro Barrientos/AP Photo)

Nick Franklin, in action during the FMX competition at the 23rd edition of Free4Style this Saturday, July 2, 2016 in Estavayer-le-Lac,Switzerland. (Photo by Jean-Christophe Bott/Keystone/APA)

Models turned into “humanoid” robots pose on a train at Waterloo Station on October 2, 2016 in London, England for the launch of new Sky Atlantic TV drama Westworld. (Photo by Matt Alexander/PA Wire)

People dressed as zombies participate in a parade for World Zombie Day 2016 in London's West End, Britain on October 9, 2016. (Photo by Splash News and Pictures)

A boy runs past one of the exhibits during the Dinosaurs exhibition in Belgrade, Serbia, Thursday, August 21, 2014. “Dino Park” has opened at Belgrade's Kalemegdan Fortress. (Photo by Darko Vojinovic/AP Photo)