U.S. Marines, left, and South Korean Marines, wearing blue headbands on their helmets, take positions after landing on the beach during the joint military combined amphibious exercise, called Ssangyong, part of the Key Resolve and Foal Eagle military exercises, in Pohang, South Korea, Saturday, March 12, 2016. North Korea said Saturday its military is ready to pre-emptively attack and “liberate” the South in its latest outburst against the annual joint military drills by the United States and South Korea. (Photo by Kim Jun-bum/Yonhap via 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)

The “EMIEW3” robot (R) demonstrates communicating with a visitor during a press preview in Tokyo on April 8, 2016. Japanese electronics giant Hitachi unveiled its humanoid customer service and guidance robot “EMIEW3” and “remote brain” robotics IT platform. (Photo by Toshifumi Kitamura/AFP Photo)

Nepalese women and young girls struggle to drink homemade alcohol poured through a pipe sticking out of the mouth of Swet Bhairab, a god of Power, during the Indra Jatra festival at Basantapur Durbar Square in Kathmandu, Nepal, 17 September 2016. Hundreds of women and young girls gathered to drink alcohol as a blessing from idol of Swet Bhairab which they believes will keep them free from all diseases. The Indra Jatra festival is celebrated to honor Indra, the king of gods and god of rains. The festival also marks the end of the monsoon. (Photo by Narendra Shrestha/EPA)

A woman jumps on a giant fried egg art installation as part of “Hecho en Casa” (Made at home) urban artwork festival in downtown Santiago, Chile, November 8, 2016. (Photo by Pablo Sanhueza/Reuters)

Students pose for a picture with a 3- D optical illusion artwork of a devastated cityscape in Aleppo, Syria at the campus of the Meiji University in Tokyo on November 18, 2016. The Japanese branch of the human rights organisation Amnesty International displayed the artwork to encourage people to think about the Syrian civil war. (Photo by Toshifumi Kitamura/AFP Photo)

A military guard carries flowers through the Cementerio Santa Ifigenia where the remains of former Cuban President Fidel Castro were entombed December 4, 2016 in Santiago de Cuba, Cuba. The tomb stands to the side of a memorial to the rebel soldiers killed in an attack that Castro led on Santiago's Moncada barracks on July 26, 1953, and in front of the mausoleum of Cuban national hero Jose Marti. (Photo by Chip Somodevilla/Getty Images)

Afghan protesters beat a policeman after a suicide attack that targeted crowds of minority Shiite Hazaras during a demonstration at the Deh Mazang Circle of Kabul on July 23, 2016. Islamic State jihadists claimed responsibility for twin explosions July 23 that ripped through crowds of Shiite Hazaras in Kabul, killing at least 61 people and wounding 207 others in apparently their deadliest attack in the Afghan capital. The bombings during a huge protest over a power transmission line could deepen sectarian divisions in a country well known for communal harmony despite decades of war. (Photo by Wakil Kohsar/AFP Photo)