Hradčany, is the district of the city of Prague, Czech Republic surrounding Prague Castle. The castle is one of the biggest in the world at about …Hradčany, is the district of the city of Prague, Czech Republic surrounding Prague Castle. The castle is one of the biggest in the world at about 570 metres in length and an average of about 130 metres wide. Its history stretches back to the 9th century. St Vitus Cathedral is located in the castle area.