Fort Kijkduin

Napoleon visited Den Helder in 1811, called it the Gibraltar of the North because of its position at the mouth of the Zuiderzee, and ordered fortification; Fort Kijkduin was built between 1811 and 1813 on the dune at Huisduinen as the main sea battery, with thick earth-covered casemates, a moat and gun positions covering the Marsdiep channel to Texel. It was used again in the Second World War as part of the Atlantic Wall and altered accordingly. It is now open with the casemates housing a North Sea aquarium - tanks built into the gun rooms holding rays, cod, lobster and a shipwreck display - along with the restored fortification, a bunker route and a lighthouse next door, the Lange Jaap of 1878, cast iron and the tallest in the country at nearly sixty-four metres, though it is closed to visitors because of structural cracking.

What you actually see

• A Napoleonic sea battery - built 1811-1813 to command the Marsdiep channel.
• An aquarium in the casemates - North Sea tanks built into the gun rooms.
• Atlantic Wall alterations - the fort reused and changed after 1940.
• The Lange Jaap - the tallest Dutch lighthouse next door, closed for cracking.

When to go

April to October. Half a day.

Honest expectations

The lighthouse is closed to visitors and has been for years because of structural problems. Casemates are cold and damp. Seasonal opening. Den Helder around it is a naval town rather than a scenic one.

Nearby

The Texel ferry leaves from Den Helder; the Navy Museum is in the port.