In this July 25, 2015 photo, youth eat a cooked pig's head as they wait for the start of carnival in Santiago, Cuba. (Photo by Ramon Espinosa/AP Photo)

First graders of a cadet's lyceum attend a ceremony to mark the start of the new school year in Kiev, Ukraine, September 1, 2015. September 1 marks the start of a new academic year for students in Ukraine.(Photo by Valentyn Ogirenko/Reuters)

Chantel Sydnor participates in the annual Sturgis Motorcycle Rally in Sturgis, South Dakota, August 4, 2015. This year marks the 75th anniversary of the rally expected to draw hundreds of thousands of motorcycle enthusiasts from around the world for events throughout the week-long festival, according to organizers. (Photo by Kristina Barker/Reuters)

A child looks at a polar bear swimming under a water in its enclosure on a hot summer day at Prague Zoo, Czech Republic, July 30, 2015. (Photo by David W. Cerny/Reuters)

A woman dressed as a Viking drinks local red wine during the annual Viking festival of Catoira in north-western Spain August 2, 2015. The festival re-enacts past Viking raids in the area and is celebrated annually on the first Sunday in August. (Photo by Miguel Vidal/Reuters)

A model presents a creation by fashion lable Dimitri at Berlin Fashion Week Spring/Summer 2016 in Berlin, Germany, July 9, 2015. (Photo by Fabrizio Bensch/Reuters)

A woman sits on the side of a street during the Grand Parade of Aalborg Carnival in Aalborg, Denmark May 23, 2015. (Photo by Henning Bagger/Reuters/Scanpix Denmark)

Vehicles move past a man resting on a taxi, as he waits for passengers, along a road in Karachi, Pakistan, May 5, 2015. (Photo by Akhtar Soomro/Reuters)