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)

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)

This undated handout picture made available on February 3, 2016 and provided by Russia's punk band Рussy Riot shows Рussy Riot frontwoman Nadezhda Tolokonnikova performing in the band's new music video titled “Chaika” in Moscow. Russian punk band Рussy Riot, which became a symbol of resistance for a church performance slamming President Vladimir Putin, released a new protest song on February 3 mocking a senior official for alleged corruption. Titled “Chaika”, the satirical song and accompanying video take aim at prosecutor general Yury Chaika, whose two sons have been accused of using their father's position to accrue large fortunes. (Photo by Andrey Noskov/AFP Photo/Russian Punk Band Рussy Riot)

A street performer dressed up as a waiter performs for at Marques de Larios street in downtown Malaga, Spain, July 4, 2016. (Photo by Jon Nazca/Reuters)

Models on the catwalk Yeezy: Season 4 show, Spring Summer 2017, New York Fashion Week, USA on September 7, 2016. (Photo by Your Name/BFA/Rex Features/Shutterstock)

An explosion at a petrochemical plant is seen in Rizhao, Shandong province, July 16, 2015. According to Xinhua News Agency, a fire broke out after the explosion, which was caused by a liquified hydrocarbon leak at the plant, on Thursday morning. There was no report of casualties yet. (Photo by Reuters/China Daily)

In this August 28, 1963 file photo, the top of the Washington Monument and part of a U.S. flag are reflected in the sunglasses of Austin Clinton Brown, 9, of Gainesville, Ga., as he poses at the Capitol where he joins others in the March on Washington. (Photo by AFP Photo)

A folk performer (front R) with make-up and props takes part in a “Blood Shehuo” parade, during a performance in Linyi county, Shanxi province March 21, 2015. “Shehuo” is the common name of Chinese traditional activities consisting of folk performances in northern China. The “Blood Shehuo” performers use make-up and props to re-enact scenes of horror in classic Chinese novels like Water Margin. (Photo by Reuters/Stringer)