Donald Trump talked a lot about building a wall between the U.S. and Mexico when he was a candidate. Now that he is president, it's unclear just what that wall is going to look like and when it might get built.
What we know so far is that it's likely to be a fence, not a wall, it won't extend the length of the border and it will be very unpopular with its southern neighbor.
At the moment, about a third of the 2,000-mile border with Mexico is fenced. Some parts are 10 feet tall, some are 20 feet, some are wire mesh, some are steel beams.