Students training to be flight attendants hold books on their heads, chopsticks in their mouths, and papers in between their knees, as they take part in a standing posture practice at a vocational school in Shijiazhuang, Hebei province, China May 4, 2017. (Photo by Reuters/Stringer)

North Korean youngsters sing and play accordions to entertain foreign visitors including United Nations Secretary General Kurt Waldheim, who visited Pyongyang, May 4, 1979. Visitors report music education in North Korea begins at an early age and is taken seriously by children and adults. (Photo by Peter Arnett/AP Photo)

Russian policewomen dressed in Soviet Army styled uniforms take part in the Victory Day parade in Volgograd on May 9, 2018. Russia marks the 73 rd anniversary of the Soviet Union' s victory over Nazi Germany in World War Two. (Photo by Mladen Antonov/AFP Photo)

Kendall Jenner attends the screening of “Girls Of The Sun (Les Filles Du Soleil)” during the 71st annual Cannes Film Festival at Palais des Festivals on May 12, 2018 in Cannes, France. (Photo by Stephane Cardinale/Corbis via Getty Images)

An adult specimen of Nannospalax (leucodon) montanosyrmiensis, a variant of the lesser mole-rat (Spalax leucodon) is pictured near Albertirsa, some 60 kilometers southeast of Budapest, Hungary, 12 May 2018. The critically endangered rodent lives in several isolated populations in the Carpathian Basin. (Photo by Sandor Ujvari/EPA/EFE)

A woman carries a floral design handbag at the RHS Chelsea Flower Show in London, Britain on May 21, 2018. The annual show of floral art, timed to coincide with the RHS Chelsea Flower Show nearby, sees over sixty shops, restaurants and local businesses compete for prizes, with the awards given by RHS (Royal Horticultural Society) judges, this year on the theme of “Summer of Love”. (Photo by Toby Melville/Reuters)

Inmates perform as cheerleaders during a soccer tournament inside the San Juan de Lurigancho prison, in Lima, Peru, Thursday, May 24, 2018. Inmates of 17 prisons, including four for women, participated in the First Interprison World Cup Lima 2018, organized by the National Penitentiary Institute. (Photoby Rodrigo Abd/AP Photo)

In this file photo taken on Saturday May 1, 1993, an elderly communist woman clutches her head as police on horseback patrol the streets in Moscow. When Alexander Zemlianichenko started working as an AP photographer in Moscow, the Soviet Union was nearing its demise. (Photo by Alexander Zemlianichenko/AP Photo)