A tourist poses for a picture with the Sphinx at the Pyramids of Giza in Cairo, Egypt, on October 19, 2011. (Reuters/Jamal Saidi)

Participants wearing masks during a hazy day at the Beijing International Marathon in front of Tiananmen Square, in Beijing, October 19, 2014. (Photo by Reuters/Stringer)

Early morning shark Sean McKeon pictured during severe flooding Oliver Plunkett street, Cork city, on February 3, 2014. (Photo by Daragh McSweeney/Provision)

A young oriental small-clawed otter at the zoo in Neumuenster, Germany, March 5, 2014. The six young otters (one male, five female) were born on December 7, 2013. (Photo by Maja Hitij/EPA)

Russian President Vladimir Putin, center, uses a binocular, as Defense Minister Sergei Shoigu, left, and chief of Russia's military's General Staff Valery Gerasimov, right, observe military exercises near the Baikal Lake on Wednesday, July 17, 2013. (Photo by Alexei Nikolsky/AP Photo/RIA Novosti/Presidential Press Service)

The anthropomorphic robot named hitchBOT sits on the shoulder of Highway 102 to begin its 6000 kilometer cross country journey outside of Halifax, Nova Scotia, July 27, 2014. The hitch hiking robot is part of a social experiment to see if drivers will pick up and drop off the robot in one piece to an art gallery in Victoria, British Columbia. (Photo by Paul Darrow/Reuters)

People ride a motorcycle near Koudoukou Mosque where Pope Francis meets Imam Tidiani Moussa Naibi in Bangui, Central African Republic, November 30, 2015. (Photo by Stefano Rellandini/Reuters)