Follow in the footsteps of Napoleon Did you know that sharks live in the North Sea? Would you dare to feed them? This is possible in the North Sea aquarium of Fort Kijkduin! A visit to the aquarium is an exciting and educational adventure where you learn everything about the underwater life in the Wadden and North Sea. Spectacular is the 15-metre-long walk-through tunnel. The historical museum of the fort is also very interesting. Walk through underground tunnels and discover 200 years of military history about Den Helder and the Napoleonic fortress itself. The new family exhibition explores the lives and work of the soldiers stationed in the fort in 1939 during the mobilization of the Dutch army.