The Castle can be visited
Tullgarn Castle

Near Trosa in the municipality of Södertälje, Tullgarn Palace is a royal estate in Sweden. This structure is known for its neoclassical interior and once served as a summer residence for members of the Swedish royal family.
History+
The origins of Tullgarn Palace date back to the late 16th century, when Count Karl Sture commissioned the first building. By the mid-17th century, the palace presented itself as a three-story main building, flanked by two round and one square tower. It was complemented by two wing buildings and another structure that enclosed a courtyard. The knight and privy councillor Tord Röriksson Bonde is named as the first known owner.
Source: Wikipedia · Licence: CC BY-SA 4.0
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 58.9500, 17.5847