The past year has seen huge strides to improve relations between Washington, Pyongyang, and Seoul. Despite THREE breakthrough summits among their leaders, the ultimate goal of denuclearization is still elusive. Our UN correspondent Liling Tan looks at where things stand now.

After more than a decade of nuclear weapons and ballistic missile tests, the launch pads and detonation sites in the Democratic People's Republic of Korea have gone silent for now. A bilateral charm offensive is underway, leading to three summits this year between the two Koreas and promises of more to come.

MOON JAE-IN SOUTH KOREAN PRESIDENT "The North has agreed to permanently close Tongchang-ri engine testing site and its missile launch facility in the attendance of experts from relevant nations."

KIM JONG UN, LEADER DEMOCRATIC PEOPLE'S REPUBLIC OF KOREA "I promised President Moon Jae-in to visit Seoul in the near future."

Each side stands to gain. The North wants to open its economy to foreign investment and development. The South wants reunification and denuclearization.

STEPHEN NOERPER, SENIOR DIRECTOR KOREA SOCIETY "The Koreas have made some real strides in confidence-building and they're talking about the elimination of a number of posts along the demilitarized zone. They've already established a liaison office at Kaesong, and the idea of communication more effectively across that formerly fortified border is important."

Detente between the two Koreas made it possible for Donald Trump and Kim Jong Un to meet and in Singapore this June, they did. Washington wants complete and verifiable denuclearization. 

MARIA ZAITSEVA, PROFESSOR OF POLITICAL SCIENCE YESHIVA UNIVERSITY "They want the suspension or the reduction of sanctions. They want security guarantees from Washington. They want normalization of relations, and they really want to be seen as a genuine player in international relations. And, the summit with Trump in June was the first step."

From the Singapore summit, a promising but vague agreement to denuclearize. Pyongyang returned the remains of American troops who fought in the Korean War, but offered no timetable for destroying its nukes.

MICHAEL JOHN WILLIAMS, PROFESSOR OF INTERNATIONAL RELATIONS NEW YORK UNIVERSITY "It's very difficult to discern from the North Korean government what their intentions are, if they're really honest in terms of denuclearization. Or, if they'll continue to use this thaw to their advantage in a positive way for both East and West, but also continue their weapons program on the side."

At this month's summit, some momentum-promises from the North to let inspectors in and an offer to demolish its primary nuclear weapons complex. That, in exchange for concessions from Washington.

LILING TAN NEW YORK "Moscow and Beijing want sanctions on the DPRK eased to reward Pyongyang for opening talks and suspending missile tests, but the U.S. is insisting the sanctions remain in place, as leverage. Washington has also accused Russia of cheating on sanctions, and called China's provision of aid and other commodities to the DPRK unhelpful. At the UN this week, with world leaders gathered here in New York, the pressure is on. Liling Tan, CGTN, at the United Nations."