Den Helder is the northernmost city on the Dutch mainland, sitting at the tip of the North Holland peninsula where the North Sea meets the Wadden Sea. It is best known as a navy town -- the Royal Netherlands Navy has been based here since the early nineteenth century -- and as the departure point for the Texel ferry to the island of Texel, one of the most popular of the Wadden Islands.
The Marinemuseum, set in the historic Willemsoord naval dockyard, is the main attraction and one of the best maritime museums in the Netherlands. You can board a submarine, walk around the minesweeper HNLMS Abraham Crijnssen — famous for disguising itself as a tropical island to escape the Japanese in 1942 — and examine the 1860s ironclad HNLMS Schorpioen, the oldest surviving Dutch warship. The Fort Kijkduin complex, a Napoleonic-era fortification, and the nearby Lange Jaap lighthouse together make for a good coastal walk.
Den Helder is not a pretty town -- wartime bombing and postwar rebuilding left it with a functional rather than charming appearance. But the surrounding coastline is dramatic, with wide beaches at Huisduinen on the North Sea side and the vast tidal flats of the Wadden Sea on the other. The ferry to Texel takes just twenty minutes and runs frequently, making Den Helder an almost unavoidable stop if you are heading to the islands.