How a quiet boy from North Korea became one of the world's scariest dictators

Reuters/KCNA KCNA

North Korean Supreme Leader Kim Jong Un greets a women's subunit during a rocket-launching drill.

For the past 50 years, the world has grown used to crazy threats from North Korea that don't lead anywhere.

But the threats have taken a decidedly sharper and more ominous tone under Kim Jong Un, the third Supreme Leader of the hermit kingdom.

On Saturday, North Korea fired a long-range rocket. This follows Pyongyang's claim to have tested a hydrogen bomb last month.

These tests have sent the UN into full crisis mode, and the organization has declared an emergency meeting on how to handle North Korea and Kim.

Here is how Kim Jong Un grew to be one of the world's most concerning world leaders.