Pupils of the Dao ethnic tribe return home from school along a hillside path at Suoi Thau village in Hoang Su Phi district of Vietnam's northern province of Ha Giang, located at the border with China, September 18, 2015. (Photo by Reuters/Kham)

Indian girls in traditional attire pose for photographs as they practice the Garba, the traditional dance of Gujarat state, ahead of Navratri festival in Ahmadabad, India, Saturday, October 3, 2015. Navratri or nine night festival will begin on October 13. (Photo by Ajit Solanki/AP Photo)

A reveller gets ready to dance during a "pow-wow" celebrating the Indigenous Peoples Day Festival in Randalls Island, New York, October 11, 2015. The festival is held as a counter-celebration to Columbus Day and is to promote Native American culture and history. (Photo by Eduardo Munoz/Reuters)

A woman rides a custom bike during "Bike Kill 12" in the Brooklyn borough of New York City, October 31, 2015. "Bike Kill" is an annual gathering of builders and riders of home-made bicycles that culminates in a tall bike jousting competition. (Photo by Stephanie Keith/Reuters)

A girl with her face painted to look like the popular Mexican figure called "Catrina", jumps as she takes part in the annual Catrina Fest in Mexico City November 1, 2015. (Photo by Carlos Jasso/Reuters)

Alfred Yetta (L) and Kay Manning pose for a photo in front of a cardboard cut-out of Pope Francis, during an event organised by Christa Scalies, the co-creator of the Pop-Up Pope, in Fado Irish Pub & Restaurant in Philadelphia, Pennsylvania, September 16, 2015. (Photo by Mark Makela/Reuters)

Workers adjust rails at the bed of a drained area of a lake used for the production of salt at the Sasyk-Sivash lake near the city of Yevpatoria, Crimea, September 25, 2015. The area has a long tradition of salt production, prepared from salt flats flooded with water from the Black Sea. (Photo by Pavel Rebrov/Reuters)

Bridegrooms pose for a photograph as they attend a mass wedding ceremony at Arena Corinthians soccer stadium in Sao Paulo, Brazil, September 26, 2015. According to the event's organizers, at least 400 couples tied the knot during a mass wedding which was organized by the Department of Justice and Citizenship of the state of Sao Paulo. (Photo by Paulo Whitaker/Reuters)