A Salvadorean clown going by the name of “Almohadita” poses during National Clown Day celebrations at Beethoven Square in San Salvador December 3, 2014. The Salvadorean congress declared the second Wednesday of December as National Clown Day to honour all Salvadorean clowns in their efforts to bring fun to the country, reported local media. (Photo by Jose Cabezas/Reuters)

A woman looks out of a dusty window after boarding a bus to be transported to see the casket of Nelson Mandela at the Union Buildings in Pretoria, South Africa, Wednesday December 11, 2013. On Thursday, December 5, 2013, Mandela died at the age of 95. (Photo by Markus Schreiber/AP Photo)

A Bangladeshi girl plays on a swing, in Dhaka, Bangladesh, December 27, 2016. (Photo by Mohammad Ponir Hossain/Reuters)

A pig's head is seen in a basin after it was slaughtered it in the village of Azerany, Belarus, December 12, 2015. (Photo by Vasily Fedosenko/Reuters)

Damaged buildings are pictured at night in Aleppo, Syria December 11, 2015. (Photo by Ammar Abdullah/Reuters)

Passengers travel on the London train and underground system during the Christmas party season, December 18, 2015. (Photo by Paul Hackett/Reuters)

A roadside currency exchange vendor sorts Indian currency notes at his stall in Agartala, India, December 6, 2016. (Photo by Jayanta Dey/Reuters)

A Husky dog looks on before a sled and skijoring race in the village of Kadnikovo outside Yekaterinburg, Russia, December 10, 2016. (Photo by Maxim Shemetov/Reuters)