The former demonstration boulevard of the GDR, the Allee is a unique site, offering a glimpse into the political and architechtural past of East Germany. It has integrated itself well into the West, offering various shops and restaurants. There is a wonderful beer shop along the Allee offering at least 300 different brews; just a little more enticement if you're into that kind of thing...
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While you're there, pop into Cafe Sybille for a coffee and a slice of cake and wander around their free exhibition of the building of Karl Marx Allee.
Is this your business?