The leaders of North and South Korean are meeting in the North Korean capital for talks centred on the stalled denuclearisation negotiations.
Since the beginning of the year North Korea has embarked on an unprecedented path of meetings with both the South and the US.
Yet talks with Washington have reached deadlock, with both sides so far agreeing only to very general goals.
South Korea has taken on a key mediating role.
South Korean President Moon Jae-in and his wife Kim Jung-sook arrived in Pyongyang on Tuesday morning for the three-day visit.
They were warmly welcomed from the plane by Mr Kim and his wife, Ri Sol-ju.
It's the first trip to the North Korean capital by a leader from the South in a decade.
It is Mr Moon's third meeting with the North's Kim Jong-un since their historic summit at the border in April this year.
The Korean War ended in 1953 with an armistice - but no formal peace treaty was signed.
What's on the agenda?
The two leaders are expected to talk about "practical measures to denuclearise" the Korean peninsula, but the specifics are not known.
When the two Korean leaders met for the first time back in April, the simple fact that they were meeting was itself a major step.
The April meeting resulted in a joint declaration to improve ties and scale down the nuclear threat.
Since then, North and South Korea have held a reunion of families separated by Korea's division, and last week set up a liaison office at the border to allow direct communication 24/7.
This week, it's thought they will look at steps towards further co-operation. Developing the economic relationship is expected to be a key theme, but one concrete outcome could also be a scaling-down of the military presence at their border, the heavily guarded Demilitarised Zone (DMZ).
Economic co-operation between North and South is nothing new. Aside from trade relations, South Korean firms once employed tens of thousands of North Korean workers in a jointly-run industrial park in the town of Kaesong, on the North's side of the border.
The project ran for more than 10 years but was suspended in 2016 after North Korea carried out its fourth nuclear test.
Seoul is also seeking to deploy its cultural power. K-pop singer Ailee, and Zico, the leader of boy band Block B, are set to perform in Pyongyang.