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

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

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

Could a modern military successfully invade and capture one of the castles or strongholds that were built during medieval times? - Quora

Which is the most famous castle in the world? - Quora

Throughout history, which civilization, kingdom, or empire was the best at building fortifications? - Quora

When were the first castles built in France? - 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 fortified historical fortresses in your opinion? - Quora

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

When did castles become obsolete as a defensive structure? - Quora