Final answer:
The city-states of Bremen and Hamburg are located in Germany, the most populous country and largest economy in Europe. Germany has a federal structure including 16 states, and these cities are unique by being both cities and federal states.
Step-by-step explanation:
The city-states of Bremen and Hamburg are located in the country of Germany. Germany is known for its historical Ruhr industrial complex and high-tech industries in cities such as Stuttgart, Mannheim, and Munich.
It has the distinction of being the most populous nation in Europe and possesses the largest economy on the continent. Bremen and Hamburg are part of Germany's federal structure which consists of 16 states, including these two cities which hold the unique status of being both cities and federal states.
Germany went through significant geopolitical changes throughout its history, with a unification in 1871 and again in 1990 after the reunification of East and West Germany. The country's central location in Europe has made it a historical hub of economic activity, culture, and politics.