So you know how sometimes you build a fence around your backyard to keep your dog in or to make sure no one comes in without asking? Well, some people think that the United States should build a really big fence (it's actually more like a wall) all along the border with Mexico to keep people from coming into the country illegally.
This is called the Trump Wall because the President of the United States, Donald Trump, really wants to build it. He believes that it will help keep people from entering the country illegally and help control the flow of drugs and crime into the United States.
However, some people don't think it's a good idea because it is very expensive to build, and it might not work the way that Trump thinks it will. They also think it could harm relationships with Mexico, as it might seem unfriendly to build a big wall like that.
So, some people like the idea of the Trump Wall, and some people don't, but it's still a topic of debate and discussion.