4. Democratic People's Republic of Korea, 1,106,000
It stands face to face against South Korea and the United States everyday along the demilitarized zone.
The army traces its roots to the late 1930s, during the time when Japan still occupied Korea.
By the time Korea was divided along the line of the 38th parallel, the northern part of the country had an armed force of around 2,500 men.
These grew during the Cold War, as North Korea fought a war against the neighboring South. Around a quarter of the country's meager budget is reserved for the military, with expenses reaching up to almost $10 billion.