A meeting between South Korean President Moon Jae-in and the DPRK leader Kim Jong Un would only be the third inter-Korean summit to take place. Here's a summary of the previous two. 

An unprecedented meeting took place in June, 2000. Then South Korean President Kim Dae-jung visited Pyongyang for an inter-Korea summit with the late DPRK leader Kim Jong Il--the first such meeting after 70 years. This meeting saw the signing of a joint communique on reconciliation, and led to a series of reunions of separated families. Later that year, Kim Dae-jung won the Nobel Peace Prize for his "Sunshine Policy" toward Pyongyang. The two sides held frequent ministerial-level talks for a few years after the summit, but they waited for seven years for the second summit between top leaders.

The 2007 summit was between Kim Jong Il and then South Korea President Roh Moo-hyun, who crossed the Demilitarized Zone in a highly symbolic moment. The summit culminated in an eight-point agreement, building on the 2000 joint communique. Both of the summits took place when South Korea was under liberal presidents who sought rapprochement with the DPRK despite conservative criticism. Now a third summit is around the corner, as South Korea has again a liberal President Moon Jae-in who was invited to visit the DPRK. This third summit is a sign that the inter-Korea relations are back on track toward peace.