in the collection on display are various items from the dutch royal family that have to do with the work of either constantijn or his son christiaan. in the display room for christiaan, various types of clockworks are shown, as well as some original clocks. family paintings and furniture are on display throughout the building, and the library of huygens (now a small office) contains many of his books, and offers the same strategic view out of the window at any boat that may appear (today one only sees highway traffic at eye level, and barge traffic at water level).