A sloth peeks out from behind a door on a floating house in the “Lago do Janauari” near Manaus, Brazil, Tuesday, May 20, 2014. Manaus is one of the host cities for the 2014 World Cup in Brazil. (Photo by Felipe Dana/AP Photo)

Bjorn, aged 5, smiles as he poses with a Owl butterfly during an event to launch the Sensational Butterflies exhibition at the Natural History Museum in London, Britain March 23, 2016. The exhibition opens to the public on March 24 and runs until September 11. (Photo by Dylan Martinez/Reuters)

Riot police clash with protesters during a rally to demand a referendum to remove Venezuela's President Nicolas Maduro in Caracas, Venezuela, September 1, 2016. (Photo by Marco Bello/Reuters)

A visitor looks at a sculpture by a Chinese artist Chen Wenling at the "Sculpture by the Sea" exhibition which runs along the Bondi to Tamarama coastal walk in Sydney on October 22, 2015. The world's largest annual free-to-the-public outdoor sculpture exhibition runs from October 22 – November 8 this year and features over 107 sculptures by artists around the world. (Photo by Saeed Khan/AFP Photo)

Military school cadets take part in a ceremony commemorating the 56th anniversary of the death of Camilo Cienfuegos who, along with Fidel Castro and Che Guevara, was a chief commander of the Cuban revolution in Havana, Cuba on October 28, 2015. (Photo by Xinhua/REX Shutterstock)

A man stands beside the Philippine flag as colorful umbrellas adorn a village hall in suburban San Juan, east of Manila, Philippines, on June 27, 2013. (Photo by Aaron Favila/Associated Press)

Sheriffs' deputies look at wreckage from the crash of Virgin Galactic's SpaceShipTwo near Cantil, California November 2, 2014. A suborbital passenger spaceship being developed by Richard Branson's Virgin Galactic company crashed during a test flight on Friday at the Mojave Air and Space Port in California, killing one crew member and seriously injuring the other, officials said. (Photo by David McNew/Reuters)

American soldiers with the 173rd Airborne Brigade Battle Company, on a battalion-wide mission in the Korengal Valley, looking for caves, weapons caches and known Taliban leaders, 2007. Tanner Stichter tends to Spc. Carl Vandeberge in the bushes moments after Vandeberge was shot in the stomach during a Taliban ambush, which killed one soldier and wounded two others. (Photo by Lynsey Addario)