Students from St Andrews University are covered in foam as they take part in the traditional “Raisin Weekend” in the Lower College Lawn, at St Andrews in Scotland, Britain October 17, 2016. The weekend, which begins on Sunday, involves rituals for new students, culminating in a foam fight on Monday morning. (Photo by Russell Cheyne/Reuters)

(L-R) Models Kylie Jenner and Kendall Jenner pose during the Universal, NBC, Focus Features, E! Entertainment Golden Globes After Party Sponsored by Chrysler held at the Beverly Hilton Hotel on January 8, 2017. (Photo by Christopher Polk/NBC/NBCU Photo Bank via Getty Images)

Igor Armicach, a doctoral student at Hebrew University's Arachnid Collection, looks onto giant spider webs, spun by long-jawed spiders (Tetragnatha), covering sections of the vegetation along the Soreq creek bank, near Jerusalem, Israel on November 7, 2017. (Photo by Ronen Zvulun/Reuters)

First year cadets of the Military University of Communication smile before an oath-taking ceremony in St.Petersburg September 6, 2014. Some 700 first year cadets of the academy attended the ceremony before starting their studies. (Photo by Alexander Demianchuk/Reuters)

(L-R) Miss Universe 2015 Pia Wurtzbach, Miss USA 2015 Olivia Jordan and Miss Teen USA 2015 Katherine Haik attend the 2016 Miss USA pageant at T-Mobile Arena on June 5, 2016 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

Israeli soldiers from the mixed-gender Lions of the Jordan battalion, under the Kfir Brigade, check their weapons at the end of the last training before being assigned their posting, on February 28, 2017, near the West Bank village of Bardale, east of Jenin. (Photo by Jack Guez/AFP Photo)

An Israeli soldier looks through her cell phone as she enjoys the Ranunculus flowers in a field in the southern Israeli Kibbutz of Nir Yitzhak, located along the Israeli- Gaza Strip border, during the Jewish holiday of Pesach (Passover) on April 12, 2017. (Photo by Menahem Kahana/AFP Photo)

A Chinese People's Liberation Army soldier marches with members of an honor guard as they prepare for a welcome ceremony for visiting Luxembourg's Prime Minister Xavier Bettel outside the Great Hall of the People in Beijing, Monday, June 12, 2017. (Photo by Andy Wong/AP Photo)