Helsinki located in the southern Finland, and has a population of 648,650. The city's urban area has a population of 1,268,296,  it’s the most important center for politics, education, finance, culture, and research. Helsinki is located 80 kilometers (50 mi) north of Tallinn, Estonia, 400 km (250 mi) east of Stockholm, Sweden, and 390 km (240 mi) west of Saint Petersburg, Russia. It has close ties with these three cities.

Together with the cities of Espoo, Vantaa, and Kauniainen, and the surrounding commuter towns,  Helsinki forms the Greater Helsinki metropolitan area, which has a population of nearly 1.5 million. Often being considered a metropolis of the EU member state. After Stockholm and Oslo, Helsinki is the third largest city in the Nordic countries. It is located in the city of Vantaa and is located in the city of Vantaa.

Helsinki was the World Design Capital for 2012,  the 1952 Summer Olympics and the 52nd Eurovision Song Contest.

Tallinn is the capital and largest city of Estonia. It is on the northern coast of the country, on the shore of the Gulf of Finland in Harju County. From the 13th century until 1918 (and briefly during the Nazi occupation of Estonia from 1941 to 1944), the city was known as Reval. Tallinn occupies an area of 159.2 km2 (61.5 sq mi) and has a population of 453,033.

Tallinn, first mentioned in 1219, received city rights in 1248, but the earliest human settlements date back 5,000 years. The initial claim over the land was laid by the Danes in 1219, after a successful raid of Lindanise led by Valdemar II of Denmark, followed by a period of alternating Scandinavian and German rule. Due to its strategic location, the city became a major trade hub, especially from the 14th to the 16th century, when it grew in importance as part of the Hanseatic League.

Riga is the capital and largest city of Latvia. With 637,827 inhabitants (2018), it is also the largest city in the three Baltic states, home to one third of Latvia's population and one tenth of the three Baltic states' combined population. The city lies on the Gulf of Riga, at the mouth of the Daugava. Riga's territory covers 307.17 km2 (118.60 sq mi) and lies 1–10 m (3 ft 3 in–32 ft 10 in) above sea level, on a flat and sandy plain.

Riga was founded in 1201 and is a former Hanseatic League member. Riga's historical centre is a UNESCO World Heritage Site, noted for its Art Nouveau/Jugendstil architecture and 19th century wooden architecture. Riga was the European Capital of Culture during 2014, along with Umeå in Sweden. Riga hosted the 2006 NATO Summit, the Eurovision Song Contest 2003, the 2006 IIHF Men's World Ice Hockey Championships and the 2013 World Women's Curling Championship. It is home to the European Union's office of European Regulators for Electronic Communications (BEREC).

In 2016, Riga received over 1.4 million visitors. It is served by Riga International Airport, the largest and busiest airport in the Baltic states. Riga is a member of Eurocities, the Union of the Baltic Cities (UBC) and Union of Capitals of the European Union (UCEU).

Klaipėda is a city in Lithuania on the Baltic Sea coast. It is the third largest city in Lithuania and the capital of Klaipėda County.

The city has a complex recorded history, partially due to the combined regional importance of the usually ice-free Port of Klaipėda at the mouth of the Akmena-Danė River. It was controlled by successive German states until the 1919 Treaty of Versailles. As a result of the 1923 Klaipėda Revolt it was added to Lithuania and has remained with Lithuania to this day, except for the period between 1939 and 1945 when it returned to Germany following the 1939 German ultimatum to Lithuania and the German–Soviet Union Molotov–Ribbentrop Pact.

The population has shrunk from the city to suburbs and the hinterland. The city had a population of 207,100 in 1992 to 157,350 in 2014 but the city is growing again. Popular seaside resorts found close to Klaipėda are Nida to the south on the Curonian Spit and Palanga to the north.

Hamburg ; officially the Free and Hanseatic City of Hamburg is the second-largest city in Germany with a population of over 1.8 million.

One of Germany's 16 federal states, it is surrounded by Schleswig-Holstein to the north and Lower Saxony to the south. The city's metropolitan region is home to more than five million people. Hamburg lies on the River Elbe and two of its tributaries, the River Alster and the River Bille.

the capital and chief port of Denmark, a city that occupies the eastern part of Zealand and northern part of the island of Amager; population 518,574 (2009).

the capital and chief port of Denmark, a city that occupies the eastern part of Zealand and northern part of the island of Amager; population 518,574 (2009).