The old military fortifications that border Christiania on the east and south sides — 17th-century earthwork ramparts with a moat — are one of the most pleasant walks in Copenhagen. The path along the top of the ramparts gives views over the water and the city, and the vegetation has been left to grow wild in a way that feels genuinely different from Copenhagen's manicured parks.
The ramparts connect Christiania to the larger network of fortification walks that ring the old city. In spring and summer, the slope facing the water is covered with wildflowers and people sunbathing. The whole circuit takes about 30 minutes at a leisurely pace.