A: Poured concrete walls are actually structural beams. To help you visualize this, think about the horizontal steel I-beams you see as a skyscraper is being built.

Trump's "great wall" was a big concrete symbol of that. Except that now it isn't even concrete. In recent weeks, he has been saying it will be made of "beautiful" steel slats.

For years, President Trump said he would build a wall out of concrete on the southern border. Now, he says it will be made of steel, not concrete.

The former real estate mogul went from an original vision of precast concrete slabs — like those used “for parking garages,” Trump told a campaign crowd in August 2015 — to a “digital ...