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)

An incredible clear-air lightning display from storms to the east of Noonamah, just outside Darwin on April 6, 2015. (Photo by Jacci Ingham/The Guardian)

A model displays the collection of Italian luxury brand Diesel at its China's first flagship shop unveiling ceremony, at Henglong Plaza on November 26, 2005 in Shanghai, China. (Photo by China Photos/Getty Images)

Kendall Jenner seen at Universal, NBC, Focus Features, E! Entertainment Golden Globes After Party Sponsored by Chrysler on Sunday, January 8, 2017, in Beverly Hills, Calif. (Photo by Eric Charbonneau/Invision for Focus Features/AP Images)

A giant Rubber Duck created by Dutch artist Florentijn Hofman is towed along Hong Kong's Victoria Habour Thursday, May 2, 2013. Since 2007 the 16.5-meter (54 feet)-tall Rubber Duck has traveled to various cites including Osaka, Sydney, Sao Paulo and Amsterdam. (Photo by Vincent Yu/AP Photo)

Raising a flag over the Reichstag is a historic World War II photograph taken during the Battle of Berlin on 2 May 1945, by Yevgeny Khaldei.

Color dyed rabbits are seen in the markets of the Souq Waqif on January 12, 2011 in Doha, Qatar. (Photo by Robert Cianflone/Getty Images)