Karlsruhe is a city in the German state of Baden-Württemberg, situated on the right bank of the Rhine near the French border. It serves as Germany's legal center, hosting the Federal Constitutional Court, the Federal Court of Justice, and the Public Prosecutor General. Located between the Mannheim-Ludwigshafen conurbation and Strasbourg, it is the third-largest city in Baden-Württemberg after Stuttgart and Mannheim.

Founded on 17 June 1715 by Margrave Charles III William of Baden-Durlach, the city was established after a dispute with the citizens of his previous capital, Durlach. It served as the capital of various Baden states until 1945. The city's layout features a central palace with thirty-two streets radiating outward like a fan, a design that defines its historical character and urban planning legacy.

The city is known as the "fan city" due to its radial street pattern, which influences the local metric geometry. Key landmarks include Karlsruhe Palace, built in 1715, which houses the Baden State Museum, and the Karlsruhe Pyramid containing the tomb of Margrave Charles III William. The city center features neoclassical buildings, while the surrounding areas include parks, forests, and residential districts.

Karlsruhe is a major hub for science and technology, home to the Karlsruhe Institute of Technology and several other colleges. It attracts visitors interested in its unique urban layout, which is considered an early example of New Urbanism. The city also hosts cultural institutions and has a reputation as a city of civil servants due to its administrative facilities.

Karlsruhe has a population of 309,050 as of 2024. It experiences an oceanic climate with mild winters and hot summers, making it one of the brightest cities in Germany. Access is provided via Karlsruhe/Baden-Baden Airport, the second-busiest in Baden-Württemberg, and extensive public transport networks connecting it to surrounding regions.