North Korea's last nuclear test had a fireball the width of 4 Manhattan blocks

businessinsider.com North Korea's nuclear weapons program is flourishing.

The Kim regime has built a host of new facilities in the recent years and a  new report from the Institute for Science and International Security  (ISIS) and Johns Hopkins University's School for Advanced International Studies found that North Korea will have enough weapons-grade nuclear material for dozens or even scores of nuclear warheads by the end of this decade.

Just what this means for international security largely depends on two factors that aren't necessarily connected to the quantity of bombs Pyongyang has on hand: miniaturization and explosive yield. North Korea needs bombs small enough to attach to long-range projectiles, and they need to pack a large explosive punch.

North Korea has conducted three nuclear tests, in 2006 , 2009 , and 2013 . As David Albright, a nuclear physicist and founder of ISIS told Business Insider, the fact that the tests were of relatively small yield suggests that North Korea has developed its nuclear weapons with miniaturization in mind.

"T he first test was a dud but it was only intended to be a low-yield test," Albright told Business Insider. "The second test wasn't that high, which is another indicator that they're working with miniaturized designs."

But the explosions were still plenty big.

Alex Wellerstein, a historian of nuclear technology at the Stevens Institute of Technology, createdthe Nuke Map to visualize the size of various nuclear detonations through history. It gives users the option of detonating a bomb with the yield of any of the three North Korean nuclear tests over any spot on earth using either an airburst or surface detonation. It even calculates injuries and fatalities.

The Nuke Map shows that the effects of North Korea's "small" nuclear detonation would be horrifying to behold.