Okay kiddo, so the United States Holocaust Memorial Museum is a really special place that helps us remember something very sad and scary that happened a long time ago.
Basically, a long time ago there was a really mean leader named Adolf Hitler who didn't like certain groups of people, like Jewish people and people who were differently-abled. He and his followers hurt and killed millions of them in a time called the Holocaust.
The museum is a place where people can go to learn about what happened during this time and honor the people who were hurt or killed. There are lots of things to see there, like pictures, videos, and even actual items that were used during the Holocaust.
It's important to remember what happened during the Holocaust so we can make sure it never happens again, and the museum helps us do that by teaching people about it.