Here's what led to President Donald Trump and North Korean leader Kim Jong Un setting up a summit in Singapore.

A South Korean soldier walks past a television screen showing pictures of US President Donald Trump (L) and North Korean leader Kim Jong Un at a railway station in Seoul on March 9, 2018. Jung Yeon-je | AFP | Getty Images

How the US and North Korea got to this point

1994: President Bill Clinton's administration and North Korea sign a deal known as the Agreed Framework. Under the terms, Pyongyang commits to freezing its illicit plutonium weapons program in exchange for U.S. construction of light-water nuclear reactors, heavy fuel, normalized relations and formal assurances against the threat or use of nuclear weapons. 2002: North Korea once again begins operating its nuclear facilities. 2003-2007: Multilateral discussions among China, Japan, North Korea, Russia, South Korea and the U.S. — known as the Six-Party Talks — seem to take a step forward when North Korea pledged to abandon its existing nuclear programs. Pyongyang also pledges to return to the Nonproliferation Treaty, which the country said it had decided to leave two years prior after originally entering it back in the 1980s. The deal appears to be a diplomatic win for the U.S. administration of George W. Bush.

2006: Pyongyang launches its first nuclear test, but the Six-Party Talks continued. 2007: North Korea begins disabling its Yongbyon nuclear plant. But that good will didn't last. 2008: The regime restarts its nuclear program and barred nuclear inspectors. 2009: North Korea officially quits nuclear talks. December 17, 2011: Kim Jong Un takes office as the third Supreme Leader of North Korea following the death of his father. March 2013: North Korea adopts an official policy of developing both the country's economy and its nuclear capabilities. January 2016: North Korea, which has continued testing its ballistic missiles technology, claims its first successful hydrogen bomb test. Some experts disputed Pyongyang's characterization of the weapon. August 2016: North Korea claims to launch a Pukkuksong-1 missile capable of striking the United States. The missile is a submarine-launched ballistic missile. October 2016: There are two failed missile launches — one was a ballistic missile, the other was an intermediate-range missile. January 2017: Trump begins his term as president of the United States. His predecessor, Barack Obama, had reportedly warned him that North Korea should be a top security priority for the incoming administration. February 2017: North Korea test-fires a new medium-range ballistic missile. The KN-15 (Pukkuksong-2) is launched from the North Pyongan province and travels 310 miles before landing in the Sea of Japan.