Prague Castle is the most popular sight visited in Prague. It is the largest ancient castle in the world (570 m long, on average 128 m wide, area 7.28 hectares).

Constructed in the 9th century by Prince Bo??ivoj, the castle transformed itself from a wooden fortress surrounded by earthen bulwarks to the imposing form it has today. Rulers made their own additions so there is a mixture of styles. Prague castle has had four major reconstructions, but it keeps its classical facelift it took on in the 18 century during the reign of Maria Theresa. The castle has three courtyards and it has always been the seat of Czech rulers as well as the official residence.