Piast Castle is a historic fortress located in Ostrów Lednicki, Poland. It was built in the 10th century and served as a royal residence for the early Polish rulers. The castle is an important symbol of the Piast dynasty, which played a crucial role in the formation of the Polish state. The castle features a unique architectural style, combining elements of Romanesque and Gothic design. Today, it is a popular tourist destination, offering visitors a glimpse into Poland's medieval history. The site also includes a museum that showcases artifacts from the early Middle Ages.