This photo illustration shows a person in Seoul on June 23, 2016 pointing to a computer screen page of the North Korean newspaper Rodong Sinmun displaying news of North Korea's Musudan missile test the day before. North Korean leader Kim Jong-Un has hailed the successful test of a powerful new medium-range missile, saying it poses a direct threat to US military bases in the Pacific, state media reported on June 23. / AFP PHOTO / JUNG YEON-JEJUNG YEON-JE/AFP/Getty Images

This photo illustration shows a person in Seoul on June 23, 2016 pointing to a computer screen page of the North Korean newspaper Rodong Sinmun displaying news of North Korea's Musudan missile test the day before. North Korean leader Kim Jong-Un has hailed the successful test of a powerful new medium-range missile, saying it poses a direct threat to US military bases in the Pacific, state media reported on June 23. / AFP PHOTO / JUNG YEON-JEJUNG YEON-JE/AFP/Getty Images

This photo illustration shows a person in Seoul on June 23, 2016 pointing to a computer screen page of the North Korean newspaper Rodong Sinmun displaying news of North Korea's Musudan missile test the day before. North Korean leader Kim Jong-Un has hailed the successful test of a powerful new medium-range missile, saying it poses a direct threat to US military bases in the Pacific, state media reported on June 23. / AFP PHOTO / JUNG YEON-JEJUNG YEON-JE/AFP/Getty Images

This June 22, 2016 handout photo courtesy of the National Science Foundation shows a Twin Otter aircraft on a medical evacuation flight taxiing on the skiway at NSF's Amundsen-Scott South Pole Station. Two sick workers were evacuated from a remote US research station near the South Pole on June 22 in a risky rescue mission carried out in the dead of Antarctica's winter, a US official said. A Twin Otter turboprop plane flew in dark and cold conditions to pick up the workers from the Amundsen-Scott station, about 250 meters from the geographic South Pole, a spokesman for the US National Science Foundation (NSF), Peter West told AFP. The plane's crew and a medical team had made the 10-hour journey to the South Pole in the middle of Antarctica's 24-hour winter on Tuesday night to reach the unidentified patients, who could not be treated on site. / AFP PHOTO / National Science Foundation / Robert SCHWARZ / RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / NATIONAL SCIENCE FOUNDATION / ROBERT SCHWARZ" - NO MARKETING - NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS ROBERT SCHWARZ/AFP/Getty Images

(FILES) This handout file photo taken on October 31, 2002 shows an aerial view of the elevated station (bottom-C) being built at the US Amundsen-Scott South Pole Station in Antarctica. Two sick workers were evacuated from a remote US research station near the South Pole on June 22, 2016 in a risky rescue mission carried out in the dead of Antarctica's winter, a US official said. A Twin Otter turboprop plane flew in dark and cold conditions to pick up the workers from the Amundsen-Scott station, about 250 meters from the geographic South Pole, a spokesman for the US National Science Foundation (NSF), Peter West told AFP. / AFP PHOTO / USAF/NATIONAL SCIENCE FOUNDATION / David McCARTHYDAVID MCCARTHY/AFP/Getty Images

This photo taken on June 21, 2016 at Publicis advertising and public relations company headquarters in Paris shows Publicis Group Directory Board Chairman, Maurice Levy during an interview. With the "Viva Technology" event, held from June 30 to July 2, 2016, the Publicis advertising and public relations group and economics newspaper Les Echos want to "put Paris on the world map of start-ups" and help large companies and start-ups to work together, says Maurice Levy. / AFP PHOTO / ERIC PIERMONTERIC PIERMONT/AFP/Getty Images

This photo taken on June 21, 2016 at Publicis advertising and public relations company headquarters in Paris shows Publicis Group Directory Board Chairman, Maurice Levy during an interview. With the "Viva Technology" event, held from June 30 to July 2, 2016, the Publicis advertising and public relations group and economics newspaper Les Echos want to "put Paris on the world map of start-ups" and help large companies and start-ups to work together, says Maurice Levy. / AFP PHOTO / ERIC PIERMONTERIC PIERMONT/AFP/Getty Images

This photo taken on June 21, 2016 at Publicis advertising and public relations company headquarters in Paris shows Publicis Group Directory Board Chairman, Maurice Levy. With the "Viva Technology" event, held from June 30 to July 2, 2016, the Publicis advertising and public relations group and economics newspaper Les Echos want to "put Paris on the world map of start-ups" and help large companies and start-ups to work together, says Maurice Levy. / AFP PHOTO / ERIC PIERMONTERIC PIERMONT/AFP/Getty Images