In this May 31, 2016 photo, pieces of watermelon litter the trash area of the Coche public market in Caracas, Venezuela. Staples such as corn flour and cooking oil are subsidized, costing pennies at the strongest of two official exchange rates. But fruit and vegetables have become an unaffordable luxury for many Venezuelan families. (Photo by Fernando Llano/AP Photo)

A vervet monkey passes in front of a woman on the shores of lake Naivasha, Kenya January 24, 2017. (Photo by Goran Tomasevic/Reuters)

A woman walks through flood water during heavy downpour at a street in Genoa, Italy, 10 October 2014. At least one person died due to flooding after heavy rains caused the Bisagno river, which runs through Genoa city to overflow. Part of the city was in black-out with flooded streets and parked cars dragged away by the water's force. (Photo by Luca Zennaro/EPA)

Bison along the Bitterroot Valley's Eastside Highway north of Stevensville, Montana, are covered in snow following a blizzard on November 23, 2010. (Photo by Perry Backus/The Missoulian)

Two carnival revellers masquerade as Leonardo da Vinci's painting “Mona Lisa” pose in St. Mark's Square in Venice, Italy, Sunday, January 31, 2016. Carnival-goers in Venice are being asked by police to momentarily lift their masks as part of new anti-terrorism measures for the annual festivities. (Photo by Domenico Stinellis/AP Photo)

A prisoner from the Pedrinhas prison is carried to receive medical help after he was injured during a fight between rival gangs inside the jail, in Sao Luiz, capital of Maranhao state, January 8, 2014. The recent posting on a major Brazilian news website of a video filmed last December 17 by Pedrinhas prisoners of the decapitated and tortured bodies of rival inmates inside the jail has highlighted some of the problems present in the country's prison system which houses nearly twice as many prisoners as its capacity, according to official statistics. (Photo by Douglas Cunha/Reuters/O Estado do Maranhão)

The British rock and roll group the Beatles talk to Ed Sullivan at CBS Studio 50 before their live television appearance on “The Ed Sullivan Show” in New York, February 10, 1964. From left to right are, Sullivan, John Lennon, Ringo Starr, holding a cigarette, and Paul McCartney. (Photo by AP Photo)

A migrant carries his belongings as he arrives at the Beijing railway station to catch a train in Beijing, Friday, February 13, 2015. (Photo by Andy Wong/AP Photo)