Kastellet

Kastellet was completed in 1664 as the northern anchor of Copenhagen's defences, a bastioned pentagon with earth ramparts, a wet moat and two gates, and it is one of the best preserved fortresses of its type in northern Europe because it has stayed in continuous military use and was never fought over into ruin. Inside the walls are rows of ochre barracks and officers' houses along a central street, a small church of 1704, a commander's house and a windmill on one bastion. The ramparts are a public path with mature trees, and walking the full circuit takes about half an hour, with views over the harbour, the Gefion Fountain and the Little Mermaid on the water below. Part of the site remains an active defence facility.

What you actually see

• The star-shaped ramparts - a bastioned pentagon walked as a path.
• Ochre barracks rows - the eighteenth-century garrison street.
• The rampart windmill - a mill standing on one of the bastions.
• Harbour views - the Gefion Fountain and the Mermaid below the walls.

When to go

Year round; the ramparts open early and close in the evening. One to two hours for the circuit. Spring for the trees and autumn for the colour. It is a favourite local running route in the mornings.

Honest expectations

Parts of the site are an active military area and closed to the public, with signs to that effect. The buildings cannot generally be entered. The ramparts are unlit in winter and close earlier. It is combined with the Little Mermaid, which draws crowds to the water below.

Nearby

The Little Mermaid is on the harbour below; the Marble Church and Amalienborg are south.