Niesytno Castle (Polish: Zamek Niesytno) was a castle in the south-west of Poland, near the village of Płonina (German name: Nimmersath), situated west of Bolków. When the castle had turned into ruins, the Płonina Palace was built at the same site, though the place is still often referred to as Niesytno Castle. It has decayed over the years, and only its ruins have remained. It is in private hands and closed for public, but is along the touristic Piastowskich Castle Route (Szlak Zamków Piastowskich).
The first mentioning of Niesytno Castle dates back to the 13th century, but it is not known by whom it was built. Legends tell of occupation by Hussite and mercenaries, and therefore it was also named Zakątek Strachu or Angstwinkel (Polish and German for "corner of fear"). From the second part of the 15th century until the 17th century, the castle was inhabited by the "von Zedlitz" lineage. It has been a military defense structure for several times. Later, the castle became a renaissance palace.
During the Second World War, German airmen (the luftwaffe) resided in the palace, preparing themselves for battle at the eastern front. The resistance used the palace as home during summer season. At that time it gradually turned into ruins. Thereafter, it was owned by the automobile manufacturer "Fabryka Samochodów Ciężarowych" from Lublin. Some repairs were carried out at that time, though neighboring population stole the building materials little by little. The palace weathered until 1990.
On 2 July 1990, while belonging to Elizabeth Zawadzkie-Malickiej from 1984, it burned down due to arson, which ruined the palace. The current state of the buildings yield even more damage. Parts of the brick walls remained after the fire.
The buildings are not open for public, but it is possible to walk around the premises and get a glimpse of what is left of the buildings. The castle is located on a hill surrounded by forest, and the remainders of the tower of the castle are visible from some distance. Most of the other parts of the ruins are hidden behind trees. Some caves can be found around the ruins, which once probably were basement and other rooms.