Why is North Korea firing so many missiles -- and should the West be worried?

Tensions are running high in the Korean Peninsula, as the United States and its allies respond to North Korea's flurry of recent missile tests -- including one that flew over neighboring Japan without warning.

Why is North Korea firing so many missiles -- and should the West be worried?
Tensions are running high in the Korean Peninsula, as the United States and its allies respond to North Korea's flurry of recent missile tests -- including one that flew over neighboring Japan without warning.