Where in the world?
The flag of North Korea has a red field with a blue stripe at the top and bottom, separated by thin white lines, and a white circle with a red star in the center.

Korea (Democratic People's Republic of)

북한

Population: 25,778,815

Region: Asia

Subregion: Eastern Asia

Capital: Pyongyang

Top Level Domain: .kp

Currencies: North Korean won

Border countries

The flag of China has a red field with five yellow stars in the top left corner, one large star surrounded by four smaller stars in a semicircle.

China

Population: 1,402,112,000

Region: Asia

Capital: Beijing
The flag of South Korea has a white field with a red and blue Taegeuk in the center and four black trigrams in each corner.

Korea (Republic of)

Population: 51,780,579

Region: Asia

Capital: Seoul
The flag of Russia has three horizontal stripes of white, blue, and red.

Russian Federation

Population: 144,104,080

Region: Europe

Capital: Moscow