“DC3 Wreck”. A capture of a US military DC3 plane wreck at the southern black beach in Iceland. Photo location: Iceland. (Photo and caption by Naian Feng/National Geographic Photo Contest)

A three-month-old Sumatran tiger cub named “Bandar” shows his displeasure after being dunked in the tiger exhibit moat for a swim reliability test at the National Zoo in Washington, on November 6, 2013. All cubs born at the zoo must take a swim test before being allowed to roam in the exhibit. Bandar passed his test. (Photo by Manuel Balce Ceneta/Associated Press)

Wadha al-Sayyed, wife of captive Lebanese soldier Khaled Moqbel, protests for his release and government action, near burning tyres blocking a road in Beirut, December 15, 2014. More than two dozen members of the Lebanese security forces are being held by Sunni Islamists. (Photo by Hasan Shaaban/Reuters)

The Mercedes-Benz F015 Luxury in Motion autonomous concept car is shown on stage during the 2015 International Consumer Electronics Show (CES) in Las Vegas, Nevada January 5, 2015. (Photo by Steve Marcus/Reuters)

Actress Angelina Jolie (L) and actor Jack Black attend the “Kung Fu Panda 2” photocall during the 64th Annual Cannes Film Festival at the Carlton Hotel on May 12, 2011 in Cannes, France. (Photo by Vittorio Zunino Celotto/Getty Images)

Musher Justin Savidis' dogs wait in the truck before the restart of the Iditarod Trail Sled Dog Race in Willow, Alaska March 6, 2016. Mushers and dog sled teams from around the world embark on the first leg of Alaska's grueling Iditarod Trail Sled Dog Race, starting a nearly 1,000-mile (1,609 km) journey through the state's unforgiving wilderness. (Photo by Nathaniel Wilder/Reuters)

North Korean leader Kim Jong Un (3rd R) and wife Ri Sol Ju (4th L) enjoy an art performance given by the Chongbong Band to mark the 70th anniversary of the founding of the Workers' Party of Korea (WPK) in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang on October 19, 2015. (Photo by Reuters/KCNA)