They are remains of a prehistoric Celtic castle over the valley of the river of Losenice on the edge of the hill called Valy. The highest situated castle in the Czech Republic can be found near the settlement of Popelná at Nicov, 5 km to the south-east of Kašperské Hory, in the area of 1st zone of the Šumava National Park. The castle has been protected as a historic landmark of the Czech Republic since 1958. After a legend the Giant Castle used to be a seat of nine giants in the past. Another legend says that the giant´s bones found here by villagers served as a foot bridge over the Losenice for many years.