Sources
Where every fact on forts.im comes from.
- Cadw: Caernarfon Castle, checked 29 Oct 2026. Used for 3 facts.
- Encyclopaedia Britannica: Krak des Chevaliers, checked 29 Oct 2026. Used for 1 fact.
- Encyclopaedia Britannica: Martello tower, checked 29 Oct 2026. Used for 4 facts.
- Encyclopaedia Britannica: White Heron Castle (Himeji), checked 29 Oct 2026. Used for 1 fact.
- Encyclopaedia Britannica: castle, checked 29 Oct 2026. Used for 3 facts.
- English Heritage: Hadrian’s Wall, history and stories, checked 29 Oct 2026. Used for 1 fact.
- English Heritage: History of Maiden Castle, checked 29 Oct 2026. Used for 5 facts.
- Historic Environment Scotland: Mousa Broch, checked 29 Oct 2026. Used for 2 facts.
- Manx National Heritage: Castle Rushen, checked 29 Oct 2026. Used for 3 facts.
- Manx National Heritage: Peel Castle, checked 29 Oct 2026. Used for 1 fact.
- UNESCO World Heritage Centre: Castles and Town Walls of King Edward in Gwynedd, checked 29 Oct 2026. Used for 3 facts.
- UNESCO World Heritage Centre: Crac des Chevaliers and Qal’at Salah El-Din, checked 29 Oct 2026. Used for 2 facts.
- UNESCO World Heritage Centre: Fortifications of Vauban, checked 29 Oct 2026. Used for 2 facts.
- UNESCO World Heritage Centre: Frontiers of the Roman Empire, checked 29 Oct 2026. Used for 4 facts.
- UNESCO World Heritage Centre: Himeji-jo, checked 29 Oct 2026. Used for 3 facts.
- UNESCO World Heritage Centre: Venetian Works of Defence between the 16th and 17th Centuries, checked 29 Oct 2026. Used for 2 facts.
Each source was checked on the date shown. We don’t list opening times, prices or other figures that change. Where a source gives an approximate date, we say “about”.