President Donald Trump’s “wall” along the U.S.-Mexico border would be a series of fences and walls that would cost as much as $21.6 billion, and take more than three years to construct, based on a U.S. Department of Homeland Security internal report seen by Reuters on Thursday. The report’s estimated price-tag is much higher than a $12-billion figure cited by Trump in his campaign and estimates as high as $15 billion from Republican House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell.