But really, the first thing you need to know about the wall is there is no wall!
It was just a political maneuver Trump used to gain votes -- pretty standard politician tactic of promising something that sounds awesome to your base and then never delivering on it.
A little known fact is while Trump waits (forever) for funding for his Southern border wall he has started construction on the Norther border wall. Turns out the communists in Canada are more of a threat than the immigrants from the south!
Trump lost his mind when he heard the US has the worlds longest undefended border with a communist dictatorship. The commies are coming over the border with Chinese and Russian soldiers Trump feels that hundreds of thousands of these commies are invading the US daily from the North!
The Northern wall has been being built in secret since 2016
Trump is a little scared the Commies are hiding a fire/ice breathing dragon which would make the wall much less effective but he still believes fire/ice breathing dragons are fake news!
Trump has also commissioned a study on the feasibility of east and west border walls as well (he wants walls of water and they will be great), he feels they can almost eliminate immigration entirely if they are physically walled off from the rest of the planet!