Pope Francis shakes hands with upon his Thursdayarrival in Seoul. The Pontiff arrived in South Korea on the first papal visit to the Asian nation in a quarter century. During his five-day visit, Francis plans to beatify 124 Korean martyrs and encourage a vibrant and growing local church seen as a model for the future of Catholicism. Gregorio Borgia/AP hide caption

itoggle caption Gregorio Borgia/AP

Chinese President Xi Jinping (right) and South Korean President Park Geun-hye greet children waving the two countries' national flags at the presidential Blue House in Seoul on Thursday. Xi has yet to visit North Korea. Kim Hong-ji/Reuters/Landov hide caption

itoggle caption Kim Hong-ji/Reuters/Landov

A propaganda painting is seen outside the People's Palace of Culture in Pyongyang, North Korea, in 2011. North Korean state media reported Friday that the nation has detained a U.S. tourist. Feng Li/Getty Images hide caption

itoggle caption Feng Li/Getty Images

North Korea apparently doesn't like either of them: President Obama and South Korean President Park Geun-hye at a news conference in Seoul, South Korea, on Friday. Carolyn Kaster/AP hide caption

itoggle caption Carolyn Kaster/AP

This image was taken Jan. 30 by astronauts aboard the International Space Station. North Korea is the large dark patch in the middle. The only significant light is from its capital, Pyongyang. The next photo adds reference points. NASA.gov hide caption

itoggle caption NASA.gov