Kwidzyn's 14th-century castle has experienced numerous ups and downs, suffering the most grievous loss in 1798 when the Prussians pulled down two sides (eastern and southern) and the main tower. Unlike many of its red-brick peers, it survived WWII unscathed. Most of the building now houses the Kwidzyn Museum, which has several sections, including displays on medieval sacred art, regional folk crafts and plenty of farming implements, as well as a display in the cellar detailing German-funded archaeological excavations.
The most curious feature of the castle is the two unusual towers standing some distance away from the western and southern sides, linked to the main building by arcaded bridges. One (the smaller tower) held a well, while the other served as the gdaniska (knights’ toilet), a long drop if ever there was one (many of the Teutonic Knights' castles had them – the origin of the name is unknown). They once stood above the river, which later changed course leaving the knights high and dry. You can visit both towers while wandering the interior, but it’s also worth seeing them from the outside.