Prague Castle ( Prazsky hrad ) is the largest medieval complex in Europe with an area 570 meters long and 7.28 hectares , it is the biggest attraction in Prague . The castle was first built in the ninth century transformed from a wooden fortress inprejmuita stone walls in an imposing building as it is today . From the complex include: St. Vitus Cathedral , museum and art galleries , Golden Lane , Lobkowicz Palace and the church of St. George .