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)

“Early morning in Mandawa, rural Rajasthan: it was the morning of Diwali and the streets were swept by smiling women in brightly coloured sarees as I took an early morning cup of chai. Celebrations started later, when darkness fell”. (Photo by Hamish Scott-Brown/Guardian Witness)

Claire McGuire (C) smiles after winning the women's snowboard division of the Bikini & Board Shorts Downhill at Crystal Mountain, a ski resort near Enumclaw, Washington April 19, 2014. Skiers and snowboarders competed for a chance to win one of four season's passes. (Photo by David Ryder/Reuters)

Arizona Cardinals cheerleader Claire Thorton, center, smiles as Air Force Capt. Eric Straub proposes to her during the first half of an NFL football game against the Washington Redskins, Sunday, October 12, 2014, in Glendale, Ariz. Thorton accepted the proposal. (Photo by Rick Scuteri/AP Photo)

“Show Time”. It's a normal behavior of mantis. They're doing defence. When they're afraid of; raising their arms and spreading their wings. They looks like smiling dancer. Photo location: Nicosia, Cyprus. (Photo and caption by Hasan Baglar/National Geographic Photo Contest)

Tour guides wearing traditional Chinese dress practice smiling by biting chopsticks at Qingming Grand-River Park in Kaifeng, central China's Henan Province on March 2, 2017, aiming to provide better service for visitors. (Photo by IPA Asia via ZUMA Wire)

A woman in yukata, casual summer kimono, poses for a photo at Fushimi Inari Taisha in Kyoto, Japan on October 2, 2019. (Photo by Matthew Childs/Reuters)

Santa Claus greets a child during a visit to residents of the slum of Petare in Caracas, Venezuela, December 11, 2016. (Photo by Ueslei Marcelino/Reuters)