President Donald Trump has set in motion his plan to build an "impenetrable, physical, tall, powerful, beautiful, southern border wall" between the US and Mexico. <br />Trump: on day one we will begin working on an impenetrable physical tall powerful beautiful southern border wall. We will use the best technology including above and below ground sensors that's the tunnels... Remember that: above and below. I say: who's going to pay for the wall, and they will scream out: Mexico. <br />I would build a great wall and nobody builds walls better than me, believe me! Mexico will pay! <br />President Trump has always insisted Mexico will pay for the Wall. Mexican President Enrique Pena Nieto has been equally insistent he will not. <br />The border is about 1,900 miles (3,100 km) long and traverses all sorts of terrain. <br />Mr Trump says his wall will cover 1,000 miles and natural obstacles will take care of the rest. <br />But how much will it cost and who is going to foot the bill? <br />What is the estimated budget? <br />"I would build a great wall, and nobody builds walls better than me, believe me, and I build them very inexpensively." <br />Mr Trump claims the total cost of the wall will be $10bn (£7.5bn) to $12bn. But estimates from fact checkers and engineers seem to be universally higher. <br />Senate Majority Leader Mitch McConnell estimated it will cost between $12-15bn, as he addressed reporters at a Republican conference in Philadelphia. <br />The 650 miles of fencing already put up has cost the government more than $7bn, and none of it could be described, even charitably, as impenetrable, physical, tall, powerful or beautiful. <br /> <br />There are other reasons the costs would be likely to escalate beyond Mr Trump's price tag - his plans require extending the wall into increasingly remote and mountainous regions, raising the building costs substantially. <br />Adding even more to the expense, the new 1,000 miles would crisscross private land, which would have to be purchased, perhaps by legal force, or financial settlements made with owners. <br />A study by the Washington Post estimated the cost of the president's wall would be closer to $25bn.
