Today, the border that divides Northern Ireland and the Republic of Ireland is "soft", in most places you could almost forget that it's there. But for decades it was a deadly flash point in the bitter conflict known as "The Troubles" . This week, we share an episode from Today, Explained) that takes a look at the history of this conflict and how Brexit could jeopardize a fragile peace.Learn more about sponsor message choices: podcastchoices.com/adchoices)NPR Privacy Policy)