Mikó Castle is the most important historical monument in Miercurea Ciuc and one of the best-preserved Renaissance fortified castles in Transylvania. Built in the 17th century at the initiative of Ferenc Mikó, the castle features impressive bastions, an elegant inner courtyard, and remarkable Renaissance military architecture. Today, it houses the Székely Museum of Ciuc, where visitors can explore exhibitions on the history, ethnography, and cultural heritage of the Székely Land.