Amsterdam is the capital city and most populous municipality of the Netherlands. Its status as the capital is mandated by the Constitution of the Netherlands, although it is not the seat of the government, which is The Hague. Amsterdam has a population of 851,373 within the city proper, 1,351,587 in the urban area] and 2,410,960 in the metropolitan area. The city is located in the province of North Holland in the west of the country but is not its capital, which is Haarlem. The metropolitan area comprises much of the northern part of the Randstad, one of the larger conurbations in Europe, with a population of approximately 8 million.

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.

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).

Aarhus is the second-largest city in Denmark and the seat of Aarhus municipality. It is located on the east coast of the Jutlandpeninsula, in the geographical centre of Denmark, 187 kilometres (116 mi) northwest of Copenhagen and 289 kilometres (180 mi) north of Hamburg, Germany. The inner urban area contains 273,077 inhabitants (as of 1 January 2018) and the municipal population is 340,421 (as of 2018). Aarhus is the central city in Business Region Aarhus and in the East Jutland metropolitan area, which had a total population of 1.378 million in 2016.

The history of Aarhus began as a fortified Viking settlement founded in the 8th century and with the first written records stemming from the bishopric seated here from at least 948. The city was founded on the northern shores of a fjord at a natural harbour and the primary driver of growth was for centuries seaborne trade in agricultural products. Market town privileges were granted in 1441, but growth stagnated in the 17th century as the city suffered blockades and bombardments during the Swedish Wars. In the 19th century it was occupied twice by German troops during the Schleswig Wars but avoided destruction. As the industrial revolution took hold, the city grew to become the second-largest in the country by the 20th century.

Oslo is the capital and most populous city of Norway. It constitutes both a county and a municipality. Founded in the year 1040 as Ánslo, and established as a trading place in 1048 by Harald Hardrada, the city was elevated to a bishopric in 1070 and a capital under Haakon V of Norway around 1300. Personal unions with Denmark from 1397 to 1523 and again from 1536 to 1814 reduced its influence, and with Sweden from 1814 to 1905 it functioned as a co-official capital. After being destroyed by a fire in 1624, during the reign of King Christian IV, a new city was built closer to Akershus Fortress and named Christiania in the king's honour. It was established as a municipality on 1 January 1838. The city's name was spelled Kristiania between 1877 and 1897 by state and municipal authorities. In 1925 the city was renamed Oslo.