How North Korean leader Kim Jong Un became one of the world's scariest dictators

• Kim Jong Un, the North Korean leader who is regarded as one of the world's most repressive and bombastic rulers, turned 35 on January 8.
• After a year of ushering in historic international peace agreements and much discussion over North Korea's nuclear arsenal, Kim's rule continues to cause concern on the world stage.
• Despite his high-profile career, there is still relatively little known of Kim.
• Here is the story of how he became one of the world's scariest dictators.

Kim Jong Un, the North Korean leader who has presided over his country's shocking, uninvited entrance into the nuclear club, turned 35 on January 8.

Kim, current head of the Kim dynasty that's ruled North Korea since the 1950s, has overseen several nuclear tests, dozens of missile tests, and the most tense, heated exchanges with a US commander in chief in his country's history.

But between threats of nuclear annihilation, brinkmanship, and attacks on South Korea, Kim — who assumed power at such a young age that many thought his rule would be doomed — has kept a firm grip on power throughout.

With all this attention, still relatively little is known of Kim.

Here's what we do know of how he grew to be one of the world's scariest dictators.

Paul Szoldra and Veronika Bondarenko contributed to a previous version of this post.

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Kim Jong Un was born on January 8 — 1982, 1983, or 1984.

His parents were future North Korean dictator Kim Jong Il and his consort, Ko Young Hee. He had an older brother named Kim Jong Chul and would later have a younger sister named Kim Yo Jong.

While Kim Jong Un's official birth year is 1982, various reports suggest that the year was changed for symbolic reasons, including that it was 70 years after the birth of Kim Il Sung and 40 years after the birth of Kim Jong Il.

But when the US Treasury Department sanctioned Kim Jong Un, the agency listed his official date of birth as January 8, 1984.

Kim, here with his mother, lived at home as a child.

During this period, North Korea was ruled by "Great Leader" Kim Il Sung. While Kim Jong Il was the heir apparent, Kim Jong Un's path to command was far less certain.

Then it was off to Switzerland to attend boarding school.

Called "Pak Un" and described as the son of an employee of the North Korean embassy, Kim Jong Un is thought to have attended an English-language international school in Gümligen, near Bern.

Kim Jong Un is described by former classmates as a quiet student who spent most of his time at home, but he had a sense of humor, too.

"He was funny," former classmate Marco Imhof told The Mirror."Always good for a laugh."

"He had a sense of humor; got on well with everyone, even those pupils who came from countries that were enemies of North Korea,"another former classmate told the German newspaper Welt am Sonntag. "Politics was a taboo subject at school ... we would argue about football, not politics."