What are some of the best fortified historical fortresses in your opinion? - Quora

What are some of the most imposing castles around the world? - Quora

What are some of the greatest fortresses ever built (they have been successful in repelling invaders and/or are impressive in terms of their size and ingenuity)? - Quora

What are some of the best castles to visit in the USA and why? - Quora

What are some benefits of having a fort or a fortress? - Quora

What are some of the greatest fortresses ever built (they have been successful in repelling invaders and/or are impressive in terms of their size and ingenuity)? - Quora

What is the most impressive Fort in Europe? - Quora

How did armies lay siege to star fortresses? - Quora

History: How do forts and castles protect towns or enforce the rulers position? - Quora

Did any non-European civilizations manage to build fortified cities/castles as formidable as those of medieval Europe prior to Europeans arriving on other continents (excluding China)? - Quora

What's the difference between a castle and a mansion? - Quora

What did Scandinavian fortifications look like during the Medieval Age? - Quora