In clockwise position: 1. The Huniad Castle. 2. Peles Castle. 3. The Palace of Culture. 4. The Brâncoveanu Palace. Thanks to Anca.
Nesvizh Castle, Belarus
Nesvizh Castle is a residential castle of the Radziwill family in Nesvizh, Belarus. The Radziwill dynasty, who built and kept the ensemble from the 16th century until 1939, gave birth to some of the most important personalities in European history and culture. Due to their efforts, the town of Nesvizh came to exercise great influence in the sciences, arts, crafts and architecture. In 2005, it was added to the UNESCO World Heritage Site list. More info here. Thanks to Xenija.