How and why North Korea developed into a nuclear power

Saturday, April 15, marks a celebration for North Korea, the anniversary of the birth of its founder, Kim Il Sung. But for the rest of the world it’s a day of wariness and worry because Kim’s grandson Kim Jong Un could use the occasion to flex the nation’s nuclear power. Yahoo News and Finance Anchor Bianna Golodryga looks at how and why this isolated, impoverished nation developed into a nuclear power.