A bodyboarder rides a wave during a big- wave surfing session at Praia do Norte in Nazare on November 19, 2016. (Photo by Patricia de Melo Moreira/AFP Photo)

Students attend a stewardess skill training for the upcoming 2017 entrance examination for art majors in colleges in Luoyang, central China's Henan Province, January 4, 2017. Along with how to stand, how to sit is also covered in these classes. (Photo by Li Bo/Xinhua/Barcroft Images)

Cropped shot of a woman flirtatiously touching leg of man in a suit with her foot under the table. (Photo by LightField Studios/Skyfish Digital Media/Getty Images)

Uniformed participant dance during a mass rally and parade in the capital's main ceremonial square, a day after the ruling party wrapped up its first congress in 36 years by elevating him to party chairman, in Pyongyang, North Korea, May 10, 2016. (Photo by Damir Sagolj/Reuters)

A nesting bird peeks out of the budding Japanese Yoshino cherry tree along the Tidal Basin in Washington, Sunday, April 7, 2013. Despite repeated predictions peak blossom time for the historic cherry trees is not yet here, but almost, almost. (Photo by Carolyn Kaster/AP Photo)

Pod of dolphins surf effortlessly through the waves in the wild traveling at speeds up to 20 mph. (Photo by Greg Huglin)

The Tribute in Light is seen behind the Empire State Building on September 10, 2011 in New York City. The Tribute in Light is an art installation honoring those who perished in the 9/11 attacks. New York City and the nation are preparing for the tenth anniversary of the terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people at the World Trade Center. (Photo by Mario Tama/Getty Images)

A young Balinese man tries to kiss a woman during the Kissing Festival known as “Omed-Omedan” at Sesetan village on April 1, 2014 in Denpasar, Bali, Indonesia. (Photo by Agung Parameswara/Getty Images)