Case 76. Map-scheme of tunnels and tunnels on Gibraltar, M 1: 5000.

Brief Summary of Case 76

Case 76 is a map and sketch of Gibraltar's galleries and tunnel system, prepared for military intelligence and operational planning purposes. The document consists primarily of a detailed diagram rather than a narrative report.

Key features shown include:

• The locations of underground galleries, tunnels, shafts, and entrances within and around the Rock of Gibraltar.
• Important military and infrastructure sites such as the waterworks, water tunnel, signal station, torpedo facilities, dockyard, marine hospital, lighthouse, and telegraph/tunnel installations.
• Defensive features including the iron fence, protected areas, tunnel access points, and connections between underground facilities.
• Geographic landmarks and military positions such as Middle Hill, El Hacho, Sandy Bay, Europa Bay, and quarry areas, showing their relationship to the tunnel network.
• A scale drawing (approximately 1:5,000) intended to help planners understand the layout of Gibraltar's underground infrastructure and key access routes.

The map itself is illustrated on page 2.

Overall, the document is a reconnaissance map showing the underground tunnel and gallery network of Gibraltar together with associated military, communications, and logistical facilities, likely intended to support planning for a possible assault on the fortress.