A castle is a type of fortified structure built during the middle ages predominantly by the nobility or royalty, and by military orders. Castles were built as defensive structures against invaders atop a hill or by the waters. Usually, they cover an extensive area because of their walls, moats, and fortifications. Often people confuse between castle and palace, but there is a clear distinction between the two.
While both are usually grand royal residences, the fortifications in a castle set them apart. The act of determining the world’s largest castles is difficult as many countries use different standards to claim their castles are the largest. For purposes of this article, only the combined area of all floors in the castle (a measurement commonly known as floorspace) is considered.
Here are the top 10 biggest castles in the world.
| Rank | Castle | Floor area |
| 1. | Malbork Castle | 143,591 m2 (1,545,601 ft2) |
| 2. | Mehrangarh Fort | 81,227 m2 (874,320 ft2) |
| 3. | Prague Castle | 66,761 m2 (718,609 ft2) |
| 4. | Windsor Castle | 54,835 m2 (590,239 ft2) |
| 5. | Hohensalzburg Fortress | 54,523 m2 (586,881 ft2) |
| 6. | Spiš Castle | 49,485 m2 (532,652 sq ft) |
| 7. | Buda Castle | 44,674 m2 (480,867 ft2) |
| 8. | Himeji Castle | 41,468 m2 (446,358 ft2) |
| 9. | Citadel of Aleppo | 39,804 m2 (428,447 ft2 |
| 10. | Edinburgh Castle | 35,737 m2 (384,670 ft2) |