Castel de Bellver 

Castel de Bellver's history and travel information by castletourist.com
Image by the_iop from Pixabay

Bellver Castle is a Gothic-style castle on a hill 3 km to the west of the centre of Palma on the Island of Majorca, Balearic Islands, Spain. It was built in the 14th century for King James II of Majorca and is one of the few circular castles in Europe.

First serving as the residence of the Kings of Majorca, and afterwards long used as a military prison throughout the 18th to mid-20th century, it is now under civilian control, being one of the main tourist attractions of the island, as well as the seat for the city’s History Museum.