The pre-siege works show why the fortress became more dangerous over time. Spanish defensive lines across the isthmus were meant to secure their side and support future attacks, but they also gave Britain a reason to strengthen Gibraltar's own defences. Fixed defences can become interactive: one side's security project may make the other side's position more legitimate, better funded, and harder to take.
Chapter · 27:57-32:07
The fortification race strengthened Gibraltar before the siege
The pre-siege section shows Spanish and British fortification projects feeding each other until Gibraltar became a harder target rather than an easier one.