Young U.S. visitors pose for a photograph next to a vintage car in Havana March 16, 2016. (Photo by Ueslei Marcelino/Reuters)

Firefighters work to quell a fire on an alleged clandestine gasoline storage in the Ixtlahuaca community, Mexico on January 5, 2016. Looting broke out at dozens of stores in Mexico on Wednesday on the sidelines of protests against a steep gasoline price increase as authorities detained more than 200 people. (Photo by Mario Vazquez de la Torre/AFP Photo)

A Soyuz MS-11 rocket carrying Russian, American and Canadian astronauts takes off from the Baikonur Cosmodrome on December 3, 2018 before reached orbit later, the first manned mission since a failed launch in October. (Photo by Kirill Kudryavtsev/AFP Photo)

A saltwater crocodile with a tyre around its neck is seen in Palu river in Palu on January 16, 2018. Indonesian conservation officials are racing against time to locate and rescue a saltwater crocodile that has had a tire wrapped around its for more than a year on the island of Sulawesi. (Photo by AFP Photo/ARFA)

People dressed as zombies participate in a parade for World Zombie Day 2016 in London's West End, Britain on October 9, 2016. (Photo by Splash News and Pictures)

Boys pan for gold on a riverside at Iga Barriere, 25 km (15 miles) from Bunia, in the resource-rich Ituri region of eastern Congo February 16, 2009. Ituri is one of many areas of the country to have experienced bitter ethnic conflict between rival tribes in recent years. Massacres have left tens of thousands dead. It is this fighting that led U.S. authorities to take the unprecedented step of naming Congo in section 1502 of the Dodd-Frank financial regulation act, which says U.S.-listed companies that source gold, tungsten, tantalum and tin from Congo or its neighbours must assure the U.S. stock exchange regulator that their business is not helping fund conflict. (Photo by Finbarr O'Reilly/Reuters)

Thousands gather to rally for marriage equality ahead of a national postal survey on September 10, 2017 in Sydney, Australia. The High Court handed down its decision on Thursday to allow the government's proposed postal ballot survey to go ahead. Ballots with the question “Should the law be changed to allow same-sеx couples to marry?” will be sent to households across Australia on September 12. (Photo by Jonny Weeks/The Guardian)

Lance Cpl. Blas Trevino of the 1st Battalion, 5th Marines, shouts out as he is rescued on a medevac helicopter from the U.S. Army's Task Force Lift “Dust Off”, Charlie Company 1-214 Aviation Regiment after he got shot in the stomach outside Sangin, in the Helmand Province of southern Afghanistan on June 11, 2011. The Army's 'Dust Off' crew needed two attempts to get him out, as they were fired upon and took five rounds of bullets into the tail of their aircraft. (Photo by Anja Niedringhaus/AP Photo/File)