A man hugs a child at the Santuario de Nuestra Senora de Guadalupe during a celebration on the Virgin of Guadalupe Day in Guatemala City, December 12, 2015. According to Catholic believers, December 12 marks the anniversary of the apparition of the Virgin of Guadalupe at the Cerro del Tepeyac in Mexico. (Photo by Jorge Dan Lopez/Reuters)

Black-headed gulls sit on pickets at a riverside in Tokyo, Japan, December 27, 2015. (Photo by Toru Hanai/Reuters)

A mother bear takes a dip in the water to cool off in the warm summer sun but refuses to leave her three youngsters behind – so they climb aboard her back. (Photo by Jon Langeland/Solent News & Photo Agency)

A woman waters the plants outside her house in an alley at a slum in Mumbai October 28, 2014. (Photo by Danish Siddiqui/Reuters)

The sun rises over the River Brue on the Somerset Levels as temperatures in parts of the south west drop below freezing, on January, 20, 2015. (Photo by Ben Birchall/PA Wire)

A member from the Iraqi security forces beats an Islamic State insurgent, who was captured in Tikrit April 1, 2015. Iraqi troops and Shi'ite paramilitary fighters were battling Islamic State on Wednesday in northern Tikrit, which officials described as the Sunni Muslim militant group's last stronghold in the city. (Photo by Alaa Al-Marjani/Reuters)

A Brazilian drug gang member nicknamed Pilintra, 26, poses with a gun atop a hill overlooking a slum in Salvador, Bahia State, April 11, 2013. One of Brazil's main tourist destinations and a 2014 World Cup host city, Salvador suffers from an unprecedented wave of violence with an increase of over 250% in the murder rate, according to the Brazilian Center for Latin American Studies (CEBELA). (Photo by Lunae Parracho/Reuters)