A man jokingly poses with a new installation of British graffiti artist Banksy's art in New York, October 20, 2013. (Photo by Carlo Allegri/Reuters)

A female member of the Ahbab Al-Mustafa Battalion holds a gun as she undergoes military training in Aleppo's Salaheddine district, June 24, 2013. (Photo by Muzaffar Salman/Reuters)

Arnaq Egede walks to the potato field on her family's farm on July 31, 2013 in Qaqortoq, Greenland. The farm, the largest in Greenland, has seen an extended crop growing season due to climate change. (Photo by Joe Raedle/Getty Images)

Indian boy Hassan Malik works in a leather shoe factory at Topsia in Calcutta, eastern India, 19 November 2013. The leather industry occupies an important place in the Indian economy. It is an employment intensive sector with a vast potential for growth and exports but also a pollution intensive industry that relies on cheap labor. One of the major production centers for leather and leather products is located in Calcutta, West Bengal. Hundreds of tanneries are operated in the city’s Tiljala, Topsia and Tangra districts. They are mostly run by local families living and working under poor conditions. (Photo by Piyal Adhikary/EPA)

July 23, 2013 – Kampala, Uganda. Helene and Diana train daily more than 2.5 hours by Innocent Kapalata, a passionate and ambitious former boxer. Amidst the shanty homes a group of ambitious fighters are trying to reach for a better life. (Photo by Peter Bauza/ZUMA Press/VISUAL Press)

“The Skeleton Krewe was founded in 1999 by Christopher Kirsch. Inspired by the early days of Carnival before tractors and floats replaced walking processions, the Krewe has become one of New Orleans' premier marching clubs. The Krewe began actively marching as a small group of friends, but has grown to 40 active members”. – The Skeleton Krewe. Photo: “The Skeleton Krewe 2013 – Manning”. (Photo by Kevin O'Mara)

Tommy Lindsey holds an enormous maple leaf that he found in Mount Vernon, Wash., October 28, 2013. Lindsey was walking with his family when he picked up the leaf that is more than two feet from stem to tip and more than 21 inches wide. (Photo by Frank Varga/The Skagit Valley Herald)

In this photo taken on Saturday, November 16, 2013, Mt. Etna, Europe's most active volcano, spews lava during an eruption as seen from Acireale, near the Sicilian town of Catania, Italy. (Photo by Carmelo Imbesi/AP Photo)