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)

A Falcon 9 SpaceX rocket, with a payload of 60 satellites for SpaceX's Starlink broadband network, lifts off from Space Launch Complex 40 during a time exposure at the Cape Canaveral Air Force Station in Cape Canaveral, Fla., Thursday, May 23, 2019. (Photo by Malcolm Denemark/Florida Today via AP Photo)

A woman carrying a basket of papayas while walking through a vegetable market in Bangkok, Thailand November 11, 2011. (Photo by Kerek Wongsa/Reuters)

On Keo Wa, 25, carries her 9-month-old baby while working at a banana plantation operated by a Chinese company in the province of Bokeo in Laos April 24, 2017. (Photo by Jorge Silva/Reuters)

Steve Jobs, CEO of Apple, attends the Macworld Conference and Expo July 18, 2001 in New York City. (Photo by Mario Tama/Getty Images)

Challenger Bulgarian heavyweight boxer Kubrat Pulev (R) lies in the ring after being knocked down by Ukrainian WBA, WBO, IBO and IBF heavyweight boxing world champion Vladimir Klitschko (L), who celebrates with his brother Vitali (2nd L), as referee Tony Weeks checks on him after their title fight in Hamburg, November 15, 2014. World heavyweight champion Vladimir Klitschko knocked out Bulgarian challenger Kubrat Pulev with a fierce left hook in the fifth round on Saturday to retain his IBF title and end his opponent's unbeaten record. (Photo by Fabian Bimmer/Reuters)

Nazi dictator Adolf Hitler greets supporters at a May Day gathering in the Olympic Stadium, Berlin. (Photo by Keystone). 1st May 1938

Hooded demonstrators vandalise a shop window in Mexico City, during the commemoration of the 50th anniversary of the 1968 Tlatelolco student massacre, on October 2, 2018. Fifty years ago, Mexican troops opened fire on student demonstrators, killing hundreds just days before Mexico City hosted the 1968 Olympics – one of the darkest episodes in a year of global turbulence. (Photo by Ronaldo Schemidt/AFP Photo)