A deeply buried World War 2 bunker accessed by a series of ladders leading approximately 10m underground from a concrete and steel hatchway. The only surface indication that the bunker exists is the presence of several mushroom ventilators and the steel access hatch with steel balustrade.

Below the ground surface is a complex of 4 rooms with steel doors. One of the rooms contains the air-conditioning system for the bunker - electric fans, which drew in air via ventilation shafts from the surface mushroom ventilators. Within the complex is evidence of many cable conduits for power and probably telephone connections.

The entire underground complex is surrounded by a circular tunnel with a drainage sump - a device also used on the battery shell magazines to control ground water seepage. The area is the vicinity of the entrance to the bunker appears to have once been well maintained with formal foot paths delineated with cobble stones.

The underground plotting room was the nerve centre of operation for the heavy guns on Robben Island. The plotting room contained contained a mechanical computer known as the "Admiralty plotting table". This machine, operated by women calculated the wind speeds, bearings, and atmospheric factors for training the heavy artillery.

The exact date of construction is unknown, however it is probably contemporary with Robben Island Battery of which the first gun was installed in 1940.

Coordinates:

• Decimal degrees: -33.81221 (Latitude) 18.37479 (Longitude)
• Degrees, Minutes & Seconds: S33 48 43 (Latitude) E18 22 29 (Longitude)
• GPS: S 33 48.733 (Latitude) E 18 22.487 (Longitude)
• UTM: 34S 257003 (X) 6255566 (Y)
• Above sea level: 79 ft / 24 m

... also on Robben Island.

Sources:

• University of Cape Town. 2001. Phase 1 Archaeological assessment of Robben Island world heritage site. Rondebosch: Archaeology Contracts Office, Department of Archaeology.