Turku Castle is Finland's largest surviving medieval castle and one of the country's most important historical landmarks. Built in the late 13th century as a simple fortress, it evolved over centuries into a magnificent royal palace. The castle witnessed significant historical events, including the imprisonment of King Erik XIV. Today it houses a comprehensive museum showcasing the city's history and medieval life, with authentically furnished halls and treasures from various eras. The Renaissance chambers and medieval dungeons offer a fascinating journey through Finnish history.