Moscow is the capital and most populous city of Russia. With over 12.5 million residents living within the city limits of 2,511 square km (970 sq mi) as of 2018, Moscow is among the world's largest cities, being the second-most populous city in Europe, the most populous city entirely within Europe, and also the largest city (by area) on the European continent.

   Moscow has one of the world's largest urban economies, being ranked as an alpha global city, and is also one of the fastest growing tourist destinations in the world. Moscow is home to the third-highest number of billionaires of any city in the world, and has the highest number of billionaires of any city in Europe.

   Situated on the Moskva River in the Central Federal District of Western Russia, the city is the northernmost and coldest megacity on Earth. With a history that dates over eight centuries, Moscow is governed as a federal city that serves as the political, economic, cultural, and scientific center of Russia and Eastern Europe.

Berlin is the capital and largest city of Germany by both area and population. Its 3,769,495 (2019) inhabitants make it the most populous city proper of the European Union.

The city is one of Germany's 16 federal states. It is surrounded by the state of Brandenburg, and contiguous with Potsdam, Brandenburg's capital. The two cities are at the center of the Berlin-Brandenburg capital region, which is, with about six million inhabitants and an area of more than 30,000 km², Germany's third-largest metropolitan region after the Rhine-Ruhr and Rhine-Main regions.  

Due to its location in the European Plain, Berlin is influenced by a temperate seasonal climate. About one-third of the city's area is composed of forests, parks, gardens, rivers, canals and lakes.

Tokyo is the capital of Japan. Tokyo forms part of the Kantō region on the southeastern side of Japan's main island, Honshu, and includes the Izu and Ogasawara Islands.

  Originally a small fishing village named Edo, the city became a prominent political center of Japan when Shōgun Tokugawa Ieyasu made the city his headquarters in 1603. When Emperor Meiji moved the imperial seat to the city from Kyoto in 1868, Edo was renamed Tokyo, literally "the Eastern Capital". The Tokyo Metropolis formed in 1943 from the merger of the former Tokyo Prefecture and the city of Tokyo. While commonly referred to as a city, Tokyo is a collective entity of multiple smaller municipalities, including 23 special wards and various bed towns in the western area.

  As of 2019, the population of Tokyo was estimated to be over 13.9 million, making it Japan's most populous prefecture. The metropolitan area is the world's most populous with over 38 million people as well as the world's largest urban agglomeration economy.

Beijing is the capital of the People's Republic of China. It is the world's most populous capital city, with over 21 million residents within an administrative area of 16,410.5 km². 

  The city, located in North China, is governed as a municipality under the direct administration of the central government with 16 urban, suburban, and rural districts. Beijing is mostly surrounded by Hebei Province with the exception of neighboring Tianjin to the southeast; together, the three divisions form the Jingjinji megalopolis and the national capital region of China.

   Beijing is an important world capital and global power city, and one of the world's leading centers for culture, diplomacy and politics, business and economy, education, language, and science and technology. A megacity, Beijing is the second largest Chinese city by urban population after Shanghai and is the nation's cultural, educational, and political center.

  The Beijing Capital International Airport has been the second busiest in the world by passenger traffic since 2010, and, as of 2016, the city's subway network is the busiest and longest in the world.

Seoul is the capital and largest metropolis of South Korea. With the surrounding Incheon metropolis and Gyeonggi province, Seoul forms the heart of the Seoul Capital Area. Ranked as an alpha world city, Seoul was the world's 4th largest metropolitan economy with a GDP of US$635 billion in 2014 after Tokyo, New York City and Los Angeles.

International visitors generally reach Seoul via AREX from the Incheon International Airport, notable for having been rated the best airport for nine consecutive years (2005–2013) by the Airports Council International.  In 2015, it was rated Asia's most livable city with the second highest quality of life globally by Arcadis, with the GDP per capita (PPP) in Seoul being around $40,000. In 2017, the cost of living in Seoul was ranked 6th globally. In 2018, Seoul's real estate market was ranked 5th in the world for the price of apartments in the downtown center.

Seoul was one of the host cities for the official tournament of the 2002 FIFA World Cup in Korea/Japan.

  Istanbul is the most populous city in Turkey and the country's economic, cultural and historic center. Istanbul is a transcontinental city in Eurasia, straddling the Bosporus strait (which separates Europe and Asia) between the Sea of Marmara and the Black Sea.

   Its commercial and historical center lies on the European side and about a third of its population lives in suburbs on the Asian side of the Bosporus. With a total population of around 15 million residents in its metropolitan area, Istanbul is one of the world's most populous cities, ranking as the world's fifth-largest city proper and the largest European city. The city is the administrative center of the Istanbul Metropolitan Municipality (coterminous with Istanbul Province).

  The city held the strategic position between the Black Sea and the Mediterranean. It was also on the historic Silk Road. It controlled rail networks between the Balkans and the Middle East, and was the only sea route between the Black Sea and the Mediterranean.