A military guard observes from a watch tower at the Combinado del Este prison during a media tour in Havana, Cuba, Tuesday, April 9, 2013. Cuban authorities led foreign journalists through the maximum security prison, the largest in the Caribbean country that houses 3,000 prisoners. Cuba says they have 200 prisons across the country, including five that are maximum security. (Photo by Franklin Reyes/AP Photo)

“What did I know about Chechnya before last week? For someone who grew up in the 1990s the very word Chechnya meant a string of grainy images on TV showing people in battered camouflage outfits, shooting at each other amid destruction and ruin. Fear, wahhabis, Shamil Basayev, terrorism, mountains: these were the words that used to spring to my mind when someone mentioned Chechnya”. – Maxim Shemetov. Photo: Special forces officers stand guard during a government-organised event marking Chechen language day in the centre of the Chechen capital Grozny April 25, 2013. (Photo by Maxim Shemetov/Reuters)

Wakodahatchee wetlands, Delray Beach, Florida, US. Equipped with sinewy necks and spear-like bills, great blue herons can lunge with fearsome speed to strike their aquatic prey. Adults will also employ rapid stabbing motions as one aspect of their complex courtship displays; they’re seemingly dangerous moves, but fitting to the intensity of mating season. (Photo by Melissa Rowell/Audubon Photography Awards)

A picture of Moon Ji-sung, a high school student who died in the Sewol ferry disaster, hangs in her room in Ansan April 7, 2015. Her dream was to be a flight attendant. Nearly a year after the Sewol ferry sank on April 16, 2014, with the death of 250 students, some families keep their children’s bedrooms intact to remember and honour their loved ones. More than 300 people, most of them students and teachers from Danwon High School, are dead, or missing and presumed dead, after the Sewol ferry sank on a routine trip from the port of Incheon, near Seoul, to the holiday island of Jeju. (Photo by Kim Hong-Ji/Reuters)

Pro-Russian activists attack policemen guarding the burned trade union building in the southern Ukrainian city of Odessa on May 3, 2014. More than 30 people were killed in a “criminal” blaze in Ukraine's southern city of Odessa, as violence spread across the country during the bloodiest day since Kiev's Western-backed government took power. Ukraine's interior ministry said at least 31 people had died in the fire Friday, with local media reporting that pro-Russian militants were believed to have been in the burning building at the time. (Photo by Anatolii Stepanov/AFP Photo)

United States Coast Guard Academy Cadets Second Class Aurimas Juodka, left, and Sheila Bertrand get in the face of “swab” Kevin Lennox as Bravo Company finishes at the barber shop and mailroom during R-Day, the reporting-in day that marks the beginning of the 7-week “Swab Summer” for the class of 2018 Monday, June 30, 2014, in New London, Conn. About 250 prospective cadets, Swabs, start the program designed to indoctrinate them to the military life of the academy and at the end will be accepted into the corps of cadets. (Photo by Sean D. Elliot/AP Photo/The Day)

Ukrainian state emblem is seen on a gun's holster as soldiers guard naval base in the village of Novoozernoye, some 91 km west of Crimean capital Simferopol, Ukraine, on Monday, March 3, 2014. Ukraine says Russian forces controlling the strategic region of Crimea are demanding that the crew of two Ukrainian warships in Sevastopol's harbor must surrender. (Photo by Ivan Sekretarev/AP Photo)