Okay kiddo, so in 2019, the leaders of two countries, North Korea and the United States, decided to have a meeting to talk about some important things. They met in a place called Hanoi, which is in Vietnam.
North Korea is a country that some people don't like because they have done bad things in the past, like making nuclear weapons that can hurt people. The United States is a big powerful country that helps other countries and wants to keep people safe.
During the meeting, the leader of North Korea named Kim Jong-un wanted some things from the United States. He wanted the United States to lift some of the sanctions that they had put on his country, which means they couldn't buy or sell some things with other countries. He also wanted the United States to stop being mean to his country and treat them better.
On the other hand, the leader of the United States named Donald Trump wanted North Korea to give up their nuclear weapons and stop trying to make any more. He wanted them to stop threatening other countries with these weapons and to make the world a safer place.
However, even though they talked for a few days, they couldn't agree on everything. The summit didn't go as planned, and they both left without a deal. This was a disappointment because people had hoped that they could come to an agreement that could help make the world a safer place.
So that's what happened at the 2019 North Korea-United States Hanoi summit, kiddo. It's important for countries to talk to each other so they can try to solve their problems and make the world a better place, but sometimes it's not easy to agree on everything.