One of Pyongyang's many historic names is Ryugyong, or "capital of willows". Photo: bronze statues of North Korean late leader Kim Il Sung and his son, Kim Jong Il at Mansu Hill, in Pyongyang © AP Photo/Jon Chol Jin

According to historians, Pyongyang is the oldest city in North Korea. It was founded in 1122. Photo: A monument of Kim Il Sung at Mansu Hill © ITAR-TASS/Boris Kavashkin

Pyongyang literally means Flat Land in Korean. Photo: Square in front of Kumsusan Palace of the Sun © ITAR-TASS/Boris Kavashkin

Kumsusan Palace of the Sun, or the mausoleum of Kim Il Sung, is one of the landmarks in the city. Photo: People in front of Kumsusan Palace of the Sun © ITAR-TASS/Boris Kavashkin

Today, Pyongyang is the main commercial, industrial, cultural and administrative center of North Korea. Photo: portrait of Kim Il Sung and Kim Jong Il on a street corner in Pyongyang © AP Photo/Wong Maye-E

According to the World Bank, the population of Pyongyang is 2.5 million people. Photo: Folk dancing held in front of the Monument to Party Founding in Pyongyang © AP Photo/Alexander F. Yuan

Kim Il-sung Square is the main city square in the center of Pyongyang, and is named after the country's founding leader, Kim Il-sung. Photo: portraits of Kim Il Sung and Kim Jong Il at Kim Il Sung Square © AP Photo/Dita Alangkara

North Korean workers in front of a replica of the Grand People's Study House at the Pyongyang Folk Park. The park spans Korean history from prehistoric to modern times © AP Photo/Ng Han Guan

Visitors walking past replicas of the Juche Tower, an ancient pagoda and statue of the Chollima, a mythical winged horse at the Pyongyang Folk Park © AP Photo/Ng Han Guan

105-story pyramid-shaped Ryugyong Hotel is the tallest building in Pyongyang. Hotel's construction was finished in 2013 © AP Photo/Wong Maye-E

The second tallest building in Pyongyang is the Tower of the Juche Idea. Inside the 170-meters obelisk, there's a lift to a viewing point on the top. Photo: tour guide standing on the top of the Tower of Juche Idea © AP Photo/Dita Alangkara

Pyongyang Metro is one of the deepest and cheapest subway systems in the world © AP Photo/Dita Alangkara

Pyongyang is divided into 19 districts and one county. Majority of North Koreans live in high-rise apartments in Pyongyang © AP Photo/Wong Maye-E

Taking into account the complete isolation of the country from the rest of the world, tourism is poorly developed in Pyongyang. Tourists mostly come from China. Photo: a bus stop in Pyongyang © AP Photo/Jon Chol Jin

Pyongyang was completely redesigned since the Korean War (1950–53). Photo: North Korean students practicing Taekwondo at the Moranbong or Moran Hill in Pyongyang © AP Photo/Wong Maye-E