{
  "$type": "site.standard.document",
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  "path": "/blog/archives/2026/04/defense-in-depth-medieval-style.html",
  "publishedAt": "2026-04-15T10:47:55.000Z",
  "site": "https://www.schneier.com",
  "tags": [
    "Uncategorized",
    "defense",
    "history of security",
    "physical security",
    "article"
  ],
  "textContent": "This article on the walls of Constantinople is fascinating.\n\n> The system comprised four defensive lines arranged in formidable layers:\n>\n>   * The brick-lined ditch, divided by bulkheads and often flooded, 15­-20 meters wide and up to 7 meters deep.\n>   * A low breastwork, about 2 meters high, enabling defenders to fire freely from behind.\n>   * The outer wall, 8 meters tall and 2.8 meters thick, with 82 projecting towers.\n>   * The main wall—a towering 12 meters high and 5 meters thick—with 96 massive towers offset from those of the outer wall for maximum coverage.\n>\n...",
  "title": "Defense in Depth, Medieval Style"
}