A ring-tailed lemur is pictured at Zoom Torino, a zoological park in Cumiana near Turin, on April 22, 2015. Zoom Torino is a new immersive zoological park, where animals can be seen without bars or cages, only natural barriers ensure the visit. (Photo by Marco Bertorello/AFP Photo)

A lioness drinks after being fed by senior keeper Glynn Hennessy at ZSL London Zoo on August 10, 2016 in London, England. Today marks World Lion Day which highlights the first global campaign to celebrate the importance and plight of lions worldwide. (Photo by Carl Court/Getty Images)

Neil Zeller's snaps were taken across Canada, where he photographs the northern lights dancing across a dark night sky. In one stunning shot, Zeller, 42, even manages to capture a flash of lightning beneath a storm cell while an aurora gives off a magnificent green glow. The photographer, from Calgary, Alberta, describes himself as a night person, and became interested in night photography about 10 years ago. (Photo by Neil Zeller/Caters News)

Turkey's Merve Aydin cries after she came in last in her women's 800m round 1 heat at the London 2012 Olympic Games at the Olympic Stadium August 8, 2012. (Photo by Lucy Nicholson/Reuters)

Casey Stoner of Australia and Repsol Honda Team rounds the bend during the third day of MotoGP testing at Sepang Circuit on February 2, 2012 in Kuala Lumpur, Malaysia. (Photo by Mirco Lazzari gp/Getty Images)

A demonstrator holds up a picture depicting Russian President Vladimir Putin with make-up, during a protest by the gay community in Amsterdam April 8, 2013. Russia does not discriminate against homosexuals, Putin told reporters in Amsterdam on Monday where he was greeted by gay rights and other activists critical of Russia's track record. Putin is on one-day visit in the Netherlands for the start of the Netherlands-Russia Year. (Photo by Cris Toala Olivares/Reuters)

New York Police Department tactical police officers stand guard near the New York Stock Exchange on September 9, 2011 in New York City. Officials are stepping up security in New York and Washington D.C. a day after U.S. officials received a credible but unconfirmed terror threat to utilize car bombs on bridges or tunnels in New York or Washington. (Photo by Justin Sullivan/Getty Images)