You should distinguish South Korea and North Korea.

Korea is divided by North Korea and South Korea.
From 1910 to 1945 Korea was invaded by Japan and became a colony,
but at last in 1945, Korea became independent from Japan.
And in 1946, Korea was divided into North Korea in Russian style and
South Korea in American style.
From that time, the division of Korea is lasting for 70 years.
The unique divided country is Korea.

Currently, North Korea is ranked to 100th in world economy....
With Vietnam and Cuba altogether, it is one of a few remained communism country.
As communism does not accept individual private property, regardless of working
volume the receiving of everyone is equalized, so it reduces the desire to work.
Therefore the whole country became poor,
and it tries to break through the poverty with 'nuclear weapon'.
Its uniqueness was enough to attract full attention of worldwide media.
North Korea is browsed in Google more than 1.2million times a month. But on the
contrary to it, South Korea and Korea are browsed less than 0.1million times a month.
Overseas media focusing exciting news pours out the news related
North Korea every day.
The military power of North Korea,
threatening world with nuclear weapon, is only ranked to 30th.

Kim JongUn is a king of North Korea. His grandfather and father were all the
kings, and now it is a era of Kim JongUn. It is a political succession.

△ the published night view by NASA 

(it shows distinct difference of economic activity in South-North)

Meanwhile, South Korea adopts democratic system. President and another every
politician are elected through the vote by people. South Korea has at the
momentum a 7th. exporting power and a 13th. economical power in a world.
On the basis of economic & cultural foundation like Samsung, LG, Hyundai Motors
and Gangnam Style it has been joined the ranks of developed countries.
Perhaps you might hear Gangnam Style of Psy with
Samsung smart phone and go to work by riding Hyundai automobile.

The reason, why you noticed only North Korea, but not know South Korea,
might lies on Google and overseas media. However,
South Korea is richer than Swiss, Australia & Spain, and similar to Italia & Canada.
Of course, with Czech, Hungary, Croatia & Mexico it is an incomparable rich country.

You should distinguish South Korea and North Korea.