Which acute threat arose during tunnel warfare by Roman legionary sappers when undermining enemy fortifications?

💡 Explanation

Suffocation was a significant risk because subterranean gas pockets, particularly methane or carbon dioxide from decomposing organic matter, would displace breathable air via diffusion. This deprivation of oxygen therefore caused asphyxiation rather than structural collapse or combustion hazards.

• Which navigational exploit became achievable when Vikings employed advanced square sail rigging?
• Which data failure occurs when humidity impacts an Inca quipu such that individual knots become indistinguishable?
• Which outcome resulted when large Roman siege engines became waterlogged during prolonged naval assaults?
• For Viking longships navigating near icebergs, which risk increased due to sea spray freezing on the sail?
• Which vulnerability increases when a Roman siege tower's wooden cladding dries excessively under prolonged sun exposure?
• Which effect limited quality of early camera obscura images projected using a pinhole as the aperture?