SEOUL, South Korea — What a difference a year makes.

North and South Korea sat down to talk Tuesday after a year of mounting tensions that saw North Korea test ever-more capable missiles and conduct its largest nuclear detonation ever, and the U.S. and its allies respond with sanctions and harsh rhetoric.

The seemingly intractable differences suddenly eased over the past week — though just a tad — in a series of developments that followed a suggestion by North Korea’s leader that he might send a delegation to the upcoming Winter Olympics in South Korea.

A look at the buildup and easing of tensions:


Jan. 1, 2017: North Korean leader Kim Jong Un says in a New Year’s address that preparations for launching an intercontinental ballistic missile have “reached the final stage.”


Jan. 2, 2017: Donald Trump, then the U.S. president-elect, tweets, “North Korea just stated that it is in the final stages of developing a nuclear weapon capable of reaching parts of the U.S. It won’t happen!”


March 6, 2017: North Korea fires four ballistic missiles, and later says it was simulating nuclear strikes on U.S. military bases in Japan.


April 12, 2017: Trump says in a televised interview that the U.S. is sending “an armada” of vessels to the Korean Peninsula, after the USS Carl Vinson aircraft carrier strike group is ordered to head there from Singapore. The move fans fears that Trump is weighing military action.


April 15, 2017: North Korea marks the birth anniversary of founder Kim Il Sung with a massive military parade. Analysts say previously unseen rocket canisters and launcher trucks point to the development of intercontinental ballistic missiles and launch systems.


June 23, 2017: North Korea’s taekwondo demonstration team arrives in South Korea for its first performance in the rival country in 10 years.


July 4, 2017: North Korea conducts its first flight test of an ICBM, the Hwasong-14. Kim says the United States would be displeased by the North’s “package of gifts” delivered on America’s Independence Day.


July 28, 2017: North Korea fires another Hwasong-14. Experts say its range could reach into the U.S. mainland, including cities such as Chicago.


Aug. 9, 2017: North Korea announces a plan to launch a salvo of missiles toward the U.S. territory of Guam, a major military hub in the Pacific. It never does.


Aug. 29, 2017: North Korea fires an intermediate-range Hwasong-12 that flies over Japan before plunging into the northern Pacific Ocean.


Sept. 3, 2017: North Korea carries out its sixth and most powerful nuclear test to date, saying it was a hydrogen bomb designed for use on ICBMs.


Nov. 29, 2017: North Korea’s third test of an ICBM demonstrates a potential range that could reach Washington, D.C.


Jan. 1, 2018: Kim says in his New Year’s address that he has a nuclear button on his desk, but also calls for improved relations with the South and says his country is willing to discuss sending a delegation to February’s Winter Olympics in Pyeongchang, South Korea.


Jan. 5, 2018: South Korea says North Korea has agreed to hold talks.


Jan. 6, 2018: Trump, expressing hope for some progress from the talks, says he is also open to talking with Kim. But his U.N. ambassador, Nikki Haley, says the next day that the U.S. administration isn’t changing its conditions regarding talks, saying Kim would first need to stop weapons testing for a significant amount of time.


Jan. 9, 2018: At a meeting in the border village of Panmunjom, North Korea agrees to send a delegation including athletes to the Olympics.