- Who
- Prague Castle
- What
- 570/128/7.28 dimension(s)
- Where
- ()
- When
- 879
The largest ancient castle in the world is Hradcany Castle or Prague Castle in Prague, Czech Republic, built in the 9th century. It is an oblong irregular polygon with an axis of 570 m (1,870 ft) and an average transverse diameter of 128 m (420 ft), giving a surface area of 7.28 ha (18 acres).
