Smiling and holding hands, North Korean leader Kim Jong Un and South Korean President Moon Jae-in met at the heavily fortified demilitarized zone.

Following a long tradition of arming U.S. presidents with political and psychological dossiers of foreign leaders ahead of critical negotiations, government analysts are gathering every new bit of information they can glean about Kim.

North Korean leader Kim Jong Un and South Korean President Moon-Jae-in will plant a commemorative tree and inspect an honor guard together after Kim walks across the border Friday for their historic summit.