The president of the United States, Donald Trump, has made it abundantly clear on many occasions that he plans to build a wall separating the USA from Mexico. His options have been narrowed down to 8 different 30×30-foot walls and one of these, or maybe all of these will serve as the wall differentiating the boundary of the US and its neighboring Mexico.
These test walls alone cost $20 million dollars and building the wall across the entire border will take the cost more than $20 billion. The prototypes for the 2,000-mile long wall are done and are currently waiting for the cement to dry before they can be tested. These walls will be tested if they can be breached, scaled or dug under once they are ready.
You can look at the prototypes and what the border patrol has to say about it in the video below: