The Wall is the Wall: Why Fortresses Fail

 …and there he corrected many abuses and was the first to construct a wall, eighty miles in length, which was to separate the barbarians from the Romans.

Interesting Great Wall Stories and Legends, Great Wall Culture

310 Sarushima Island Images, Stock Photos, 3D objects, & Vectors

Theodosian Walls

21 of the Great Fortresses Around the World

Uzbekistan Print Black And White, Uzbekistan Wall Art, Uzbekistan Poster, Uzbekistan Photo Canvas Poster Wall Art Decor Print Picture Paintings for Living Room Bedroom Decoration 16x24inch(40x60cm): Posters & Prints

Tuesday Q&A: History has given us a wealth of walls to study so do they work?, WWU News

Freelance Flaneur: The quite good wall of South Korea

What was 'the Atlantic Wall,' and why did it fail? - Quora

10 Facts About Hadrian's Wall