Which vulnerability appeared earliest in Roman fortifications when attackers undermined the wall foundations?

💡 Explanation

When undermining fortifications, attackers create tunnels beneath walls removing soil support which induces collapse because soil bearing capacity locally decreases around the tunnel, leading to structural imbalance. Therefore wall collapse results directly, rather than gate or tower failure and rampart breach that require other mechanisms like impact, material degradation or direct assault.

• Which navigational error increases most when a 18th-century mariner sights the sun using a sextant from tilting ship?
• Which structural problem frequently affected wooden ship hulls during 18th-century transatlantic voyages?
• Which limitation increased navigational risk when using early marine chronometers aboard 18th-century sailing vessels?
• Which mechanism enabled Ibn al-Haytham's (Alhazen) accurate descriptions of image formation via pinhole?
• Which drawback limited the effectiveness of Roman torsion artillery during prolonged sieges in damp climates?
• What consequence results from inaccurate index mirror adjustment due to thermal expansion aboard an 18th-century sextant?