This bat gives a cheeky smile as he gobbles down his food at Singapore Zoo, on September 10, 2013. (Photo by Benny Iskander/HotSpot Media)

A reveller smiles as she walks in the rain at Worthy Farm in Somerset during the Glastonbury Festival in Britain, June 28, 2015. (Photo by Dylan Martinez/Reuters)

A man smiles as he carries firewood he bought on a street amid ongoing fuel and cooking gas shortages in Yemen's capital Sanaa December 2, 2015. (Photo by Khaled Abdullah/Reuters)

A lady smiles during the annual Calabar cultural festival in Calabar, Nigeria, December 28, 2015. Picture taken December 28, 2015. (Photo by Reuters/Stringer)

A girl smiles as her hair is blown by a strong wind in the Chinatown area in Yokohama, near Tokyo, Friday, January 27, 2017. (Photo by Koji Sasahara/AP Photo)

A young USA fan smiles ahead of the 2019 Concacaf Gold Cup semifinal football match between USA and Jamaica on July 3, 2019 in Nashville, Tennessee. (Photo by Ricardo Arduengo/AFP Photo)

A participant smiles at the annual Christopher Street Day parade on Kurfuerstendamm in Berlin, Germany, June 27, 2015. (Photo by Fabrizio Bensch/Reuters)