Donald Trump stepped onto North Korean soil Sunday as he met Pyongyang's leader Kim Jong Un in the Demilitarized Zone dividing the peninsula, in a symbolic diplomatic spectacle and a first for any American president. After shaking hands with Kim over the line that marks where their two countries and their allies fought each other to a standstill in the 1950-53 Korean War, Trump walked for several steps into North Korean territory, before another handshake.