First, they stop taking your calls. Then they blow up the house. But this isn't a love affair gone wrong, it's what's happening right now along one of the tensest borders in the world, between North and South Korea. Last week Pyongyang quit answering a daily phone call from the South that was set up in 2018 to keep the peace and further reconciliation. Then, yesterday, North Korea quite literally blew up a building just north of the border which both sides had used for the past two years as a meeting place for officials from the North and the South.