The inundation and interlocking batteries close Gibraltar's approaches

This watch point shows how Gibraltar's engineers converted geography into a layered defence. The inundation flooded the approach to Landport Gate and concealed trenches and traps, leaving only narrow passages covered by grapeshot; Devil's Tongue Battery could then fire across the isthmus from the flank. Although grapeshot lost much of its effect beyond roughly one hundred yards, ten or twelve guns aimed at each confined approach could sustain suppressive fire. Green's larger program repaired walls, improved magazines and barracks, and culminated in King's Bastion, whose guns dominated the bay while also sweeping the sea walls in both directions.