A knife is seen beside a bowl containing blood after a ram was killed as a sacrifice in front of a shrine at the annual voodoo festival in Ouidah, Benin, January 10, 2016. In Ouidah, a small town and former slave port in the West African country of Benin, the annual voodoo festival gathers visitors from far and wide. It's a week that brings together priests and dignitaries, rich and poor, locals and visitors from as far afield as the Caribbean and France. The festival commemorates the estimated 60 million people who lost their homelands and their freedom during the African slave trade. (Photo by Akintunde Akinleye/Reuters)

Larissa Neto, a muse of the Unidos da Tijuca Samba School, poses as she wears a carnival dress in Sao Goncalo near Rio de Janeiro, Brazil, February 3, 2016. Rio de Janeiro's carnival parades are known the world over for the glitz and glamour, high-tech allegorical floats and shimmering bodies, which battle it out each year for the championship title. Each school is fronted by the Queen of the Drums, who dances alongside the raging percussion, and her court of sparkling, sculpted dancers known as “muses”. (Photo by Ricardo Moraes/Reuters)

A man carrying an axe walks past a house marked with bullet holes in Gyallesu district after recent clashes between Shi'ites and the army in Zaria, Kaduna state, Nigeria, February 3, 2016. Sectarian tensions are rising in Nigeria's Muslim north, where hundreds of Shi'ites were killed in clashes with the army in the town of Zaria in December, according to Shi'ites and rights groups. Following the clashes, bulldozers sent by the state levelled Shi'ite shrines, a cemetery and offices in the deeply divided town. The region is already grappling with an insurgency waged by the jihadist Boko Haram group. (Photo by Afolabi Sotunde/Reuters)

The British Breitling Wingwalkers, Danielle Hughes and Emily Guilding, soar above the Palm Jumeirah in Dubai at 1,500 feet (460 meters) in excess of 100mp/h, ahead of their Dubai debut performance at the 2014 UIM Skydive Dubai XCAT World Powerboating Series, on Saturday, 13th December 2014. The British team is the only aerobatic formation display team who employ full time wingwalkers and fly their two Breitling-liveried 1930's Boeing Stearman bi-planes at Air Shows and major sporting events around the world. (Photo by Katsuhiko Tokunaga/Breitling via AP Images)

Chinese artist Kong Ning poses in a costume symbolizing a butterfly, which is decorated with 365 masks on its wings to represent the number of days in a year, during her performance art at the Badaling section of the Great Wall on the outskirts of Beijing January 1, 2015. Kong, whose works include themes related to China's air pollution problem, named her new performance art “Hua Die” (transforming into a butterfly) and performed it on the first day of the new year as she hopes that China has clean air for this year. (Photo by Kim Kyung-Hoon/Reuters)

Alex “Torreto” Vellios, a 26-year old barber sports his tattoo of an open razor as he holds a real razor while preparing for his first customer of the day at his Torreto barber shop in Frankfurt, January 6, 2015. Inspired by a childhood trip to the barbers with his grandfather in Greece, Vellios, a formally trained hairdresser and self-taught barber, fulfilled his dream of opening his own gentleman's barber shop five months ago and has turned it into a successful male grooming and shaving business with customers now waiting up to three to four weeks for an appointment to see him. (Photo by Kai Pfaffenbach/Reuters)

“The Amazon river has a newly discovered source. Completed last year and led by West Hansen and documented by award-winning freelance photographer Erich Schlegel, this is the first expedition to paddle from the furthest source of the earth's largest river to the ocean”. – zReportage. Photo: August 19, 2012 – Alpamarca, Peru – Amazon Express white water members Juan Antonio De Ugarte, of Peru, Rafael Ortiz, of Mexico, West Hansen, of the U.S., and Tino Specht, of the U.S., paddle down the Rio Gashan after leaving Lago Acucocha. Lago Acucocha is possibly the dry season source of the Amazon River. (Photo by Erich Schlegel/zReportage via ZUMA Press)

Maj. Matt O'Donnell of Glenelg, MD shields himself from rotor wash as Ospreys carrying the delegation of U.S. Secretary of Defense Leon Panetta leaves on March 14, 2012 at Forward Operating Base Shukvani, Afghanistan. Panetta is also scheduled to meet with President Karzai during his two-day visit to Afghanistan. The trip comes as the Taliban has vowed revenge following this past weekend's killing spree by a U.S. soldier who is accused of killing 16 civilians in Afghanistan. Most of those killed were children and women. (Photo by Scott Olson/Getty Images)