UConn students from Storrs, Conn., Gary Tu, Danny Wang and Victor Zheng, fish at Shenipsit Lake in Tolland, Conn. during sunset on Tuesday, August 19, 2014. (Photo by Jim Michaud/AP Photo/Journal Inquirer)

A student uses a ruler to measure the distance between forks before a formal dinner at The International Butler Academy China on September 16, 2014 in Chengdu, China. Over the last several years, there has been a surge in demand among China's wealthy for Western-trained butlers, with many academies seeing large portions of their graduating classes hired by Chinese families or companies. (Photo by Taylor Weidman/Getty Images)

A student from the General Yermolov Cadet School takes part in weapons training during a two-day field exercise near the village of Sengileyevskoye, just outside the south Russian city of Stavropol April 13, 2014. The General Yermolov Cadet School in the southern Russian city of Stavropol is a state-run institution that teaches military and patriotic classes in addition to a normal syllabus. (Photo by Eduard Korniyenko/Reuters)

This picture taken on December 17, 2013 shows people taking photos of a pole dancer (R) practising after it snowed in Tianjin during a promotional event by members of China's national pole dancing team and students of the sport. China set up its first national pole dancing team in Tianjin in 2012 in order to compete in the World Pole Dancing Championships. (Photo by AFP Photo)

Students of the General Yermolov Cadet School take part in combined military training with members of a local youth military patriotic club at a boot camp of the Russkiye Vityazi (Russian Knights) military patriotic club in the village of Sengileyevskoye outside Stavropol, Russia February 8, 2017. (Photo by Eduard Korniyenko/Reuters)

South Korean students pose for a selfie following a traditional coming-of-age ceremony at Namsan hanok village in Seoul on May 15, 2017. The Coming of Age Day is the day to celebrate and encourage the youth who have reached the age of 20, which is considered the beginning of adulthood. (Photo by Ed Jones/AFP Photo)

A hooded protester throws a petrol bomb to riot policemen during clashes, following a rally marking the 43rd anniversary of a 1973 student uprising against the military dictatorship that was ruling Greece, in Athens, Greece, November 17, 2016. (Photo by Yannis Behrakis/Reuters)

Students pose for a picture with a 3- D optical illusion artwork of a devastated cityscape in Aleppo, Syria at the campus of the Meiji University in Tokyo on November 18, 2016. The Japanese branch of the human rights organisation Amnesty International displayed the artwork to encourage people to think about the Syrian civil war. (Photo by Toshifumi Kitamura/AFP Photo)