In September 2017, North Korea shocked the world by exploding the most powerful nuclear device tested anywhere in 25 years.
Today, North Korea\'s nuclear weapons stockpile and ballistic missile arsenal continues to grow, presenting one of the most serious challenges.
By the end of that year, Kim Jong Un, the reclusive state\'s ruler, declared that his nuclear deterrent was complete.
Months earlier, it had conducted the first test flight of a missile capable of ranging much of the United States.
In September 2017, North Korea shocked the world by exploding the most powerful nuclear device tested anywhere in 25 years