Controversial walls in history and Trump's border wall

A wall, in its most basic form, is a physical barrier. In isolation, it's not political. But a wall can also keep people out, hold people in and almost always create some sort of divide. In China it’s a defense system turned national landmark, in Berlin it’s an infamous blockade, and in America it’s an emblem of a fiery, divisive, political debate. So how will this time be remembered in history, if at all? Watch the video to find out what history can tell us about the U.S.-Mexico border today.