The division of the Korean Peninsula was a product of the Cold War. Until the collapse of the Soviet Union, U.S. diplomacy with Pyongyang was non-existent. That changed in the 1990's. As concern grew over the DPRK's plans to withdraw from the nuclear non-proliferation treaty, Washington looked for a potential deal with Pyongyang. Twenty-five years of misunderstandings and missed opportunities followed. CGTN's Nathan King looks back on the diplomatic dance between Washington and Pyongyang.

The end of the Cold War also meant the withdrawal of tactical nuclear weapons by the U.S. - and the then Soviet Union - from global hot spots, including the Korean Peninsula. U.S. troops remained at the DPRK border.

In 1994, former U.S. President Jimmy Carter went to Pyongyang in a bid to persuade DPRK leader Kim Il Sung to halt construction on nuclear reactors.

Later that year, Washington and Pyongyang signed the "Agreed Framework", freezing work on the reactors - and production of plutonium - in return for fuel shipments and economic aid.

The diplomacy, though difficult, bore fruit. In 2000, DPRK senior military leader Jo Myong Rok met with U.S. President Bill Clinton. Then U.S. Secretary of State Madeline Albright travelled to Pyongyang to meet leader Kim Jong Il in a bid to expand the Agreed Framework and pave the way for a presidential visit to Pyongyang. The attempt failed.

 But in 2002 George W. Bush, a new president, in response to the 911 terror attacks, declared an "Axis of Evil," lumping Pyongyang in with Washington's enemies in the Middle East. John Bolton, now National Security Adviser, but then in charge of arms control at the State Department, accused the DPRK of cheating.

Pyongyang accused Washington of reneging on its commitments and the Agreed Framework fell part. In 2003, blaming U.S. aggression, Pyongyang pulled out of the nuclear nonproliferation treaty-a signal that a nation is contemplating building an atomic bomb.

After Pyongyang withdrew from the nonproliferation treaty, regional powers led by China held a series of so-called six-party talks. Despite intense diplomacy Washington and Pyongyang remained at odds. In 2006, the DPRK conducted its first nuclear test. Sanctions followed. Even though the six-party talks lasted until 2009, a breakthrough remained elusive.

Under Barack Obama, the U.S. then embarked on a period of what it called "strategic patience"-trying to bring Pyongyang to the negotiating table with economic sanctions. A new DPRK leader, Kim Jong Un, banned international weapons inspections as he moved forward with a nuclear weapons program at an accelerated pace. The election of U.S. President Donald Trump coincided with an escalation of nuclear and ballistic missile testing by Pyongyang and an escalation in hostile rhetoric from both leaders.

DONALD TRUMP US PRESIDENT "Rocket Man is on a suicide mission for himself and for his regime. The United States is ready, willing and able, but hopefully this will not be necessary."

Both leaders threatened nuclear war. Kim Jong Un responded in a rare personal rebuke, calling the U.S. president a "dotard". But, a turnaround came just as fast. Capitalizing on a peace offering made by Kim Jong Un in his New Year's address, South Korean President Moon Jae-in invited the DPRK to compete in the Winter Olympics. The two Koreas walked out as one team. Diplomatic meetings were held. Two months later-a proposed summit.

Two visits to Pyongyang by U.S. Secretary of State Mike Pompeo, lots of behind the scenes diplomacy and one cancellation letter from the U.S. president led to the highest level meeting between the two nations in nearly 20 years, setting the stage for a historic summit.

NATHAN KING WHITE HOUSE "While the Singapore summit is historic, in a way it's going against history. In the past, Pyongyang and Washington have negotiated the details in private first, distrustful diplomacy behind the scenes, but these two leaders have taken a gamble, the top-down diplomacy may work this time, and some agreement may happen in Singapore, without anything really being on the table beforehand. The risks are high, but so could be the rewards. Nathan King, CGTN at The White House."