Royal Netherlands Naval College (Koninklijk Instituut voor de Marine)

Allein schon das Gebäude ist beeindruckend.

The main building of the Royal Netherlands Navy Institute, located in the northeastern compartment of Rijkswerf Willemsoord. The extensive INSTITUTE, built in 1869-1870, was probably designed by architect Van Oudshoorn. The architectural style is eclectic with many Neo-Renaissance elements. The client was the then Minister of the Navy L.G. Brocx. In the specifications, the function of the building was described as "housing and education of midshipmen for the Royal Navy in Willemsoord". On February 26, 1869, the foundation (pile foundation and trassram) of the building was tendered to contractor M. Deutekom in Amsterdam for f.47,747.=. On June 11, 1869, the erection and finishing of the building was tendered to contractor P. van Limburgh in Rotterdam for f.193,000.=.
(rijksmonumenten.nl/monument/508461/hoofdgebouw-koninklijk-instituut-voor-de-marine-kim-object-q/den-helder/)

Oh yes, the submarine is in the Navy Museum, not here.

The training institute for future officers of the Dutch Royal Navy. You can join a guided tour every Saturday and Wednesday afternoon. Registration in advance via the KIM website is mandatory.