Interesting that prior three nuclear tests in 2006, 2009 and 2013 were all at Punggye-ri....and Researchers at the US-Korea Institute at Johns Hopkins University said last month that recent satellite images showed North Korea was excavating a new tunnel at Punggye-ri.
![](http://www.freemalaysiatoday.com/wp-content/uploads/2016/01/nkorea.jpg)