Protesters use fireworks against riot police during clashes in the Athens neighborhood of Exarchia, a haven for extreme leftists and anarchists, Thursday, December 6, 2018. New protest marches were underway in Greece Thursday evening on the 10th anniversary of the fatal police shooting of a teenager, hours after violent initial demonstrations where masked youths attacked police with firebombs and stones. (Photo by Yorgos Karahalis/AP Photo)

Indians pause to pray after lighting candles as they and other Christians gather to celebrate Christmas at the Sacred Heart Cathedral on Christmas Day, December 25, 2011 in New Delhi, India. (Photo by Daniel Berehulak /Getty Images)

A dog dives during a pet dog swimming contest at the Taoyuan Pet Center on July 31, 2005 in Chengdu of Sichuan Province, southwest China. Over 30 dogs have attended the match. According to state media, with the country's pet population growing fast, analysts predict that the market potential for the “pet economy” in China could reach a minimum of RMB 15 billion (about USD 1.85 billion). (Photo by China Photos/Getty Images)

Odin, a five year-old White Bengal Tiger dives for a piece of meat thrown to him by a trainer during a big cat show at Six Flags Discovery Kingdom June 1, 2007 in Vallejo, California. Unlike most cats that are afraid of water, Odin loves diving in the pool to retrieve bits of meat fed to him by his trainers. (Photo by Justin Sullivan/Getty Images)

Japanese team trains before the 6th FINA Synchronised Swimming World Trophy at the Water Cube on December 8, 2011 in Beijing, China. (Photo by Feng Li/Getty Images)

Inmates dressed as Santa Claus prepare to participate in an event ahead of Christmas celebrations at Santa Monica female prison in Lima December 19, 2014. (Photo by Enrique Castro-Mendivil/Reuters)

St Mary's Cathedral is illuminated as part of a Christmas lights display in celebration of Christmas on December 19, 2014 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)