Dortmund is the largest city in the Ruhr and synonymous with two things: football and beer. Borussia Dortmund's Signal Iduna Park (the Westfalenstadion) holds over 80,000 fans and the "Yellow Wall" south stand is the largest standing terrace in European football. Even if you are not a football fan, the atmosphere on a match day is something.
The city was heavily bombed in the Second World War and rebuilt in a functional postwar style, so the centre is not beautiful. But Dortmund has good museums — the Dortmunder U, a former brewery turned cultural centre, houses contemporary art and a rooftop cinema. Zeche Zollern, a spectacularly ornate former coal mine on the outskirts, is one of the finest industrial monuments in Germany.
Dortmund has brewed beer since the Middle Ages and was once Germany's largest brewing city. Several breweries remain, and the local Dortmunder Export style — malty, clean, and less hoppy than a Pilsner — is worth seeking out. In the old city centre, the medieval churches Reinoldikirche and Marienkirche stand close together on the Hellweg, and the Steinwache memorial museum near the Hauptbahnhof documents the city under National Socialism with unusual honesty.