The centrepiece of Trakai is its picture-postcard Island Castle atop an island on Lake Galvė. The painstakingly restored red-brick Gothic castle probably dates from around 1400, when Gran Duke Vytautas needed stronger defences than the peninsula castle afforded. The castle closes on Mondays between October and March, and charges €1.16 for photography in its grounds.
A footbridge links it to the shore and a moat separates the triangular outer courtyard from the main tower with its cavernous central court and a range of galleries, halls and rooms. Some house the Trakai History Museum, which charts the history of the castle. The castle's prominence as a holy site is reflected in its collection of religious art. In summer the castle courtyard is a magical stage for concerts and plays.