President Donald Trump made history last month when he became the first U.S. President to cross the De-Militarized Zone (DMZ) into North Korea. Because diplomatic relations between the U.S. and North Korea have been hostile dating back to the Korean War, the President has many wondering about the diplomatic implications of this meeting. In this hour of River to River, host Ben Kieffer talks with historian Tim Walch and political scientist Jim McCormick about notable presidential visits abroad in U.S. history, such as Franklin D. Roosevelt at the Yalta Conference, John F. Kennedy and Ronald Reagan in Berlin, Richard Nixon's visit to China and Barack Obama in Cuba. Guests include: Tim Walch, emeritus director of the Herbert Hoover Presidential Library and Museum Jim McCormick, professor of political science at Iowa State University