A whole complex of around 100 silos appear to have existed within the Citadel. Some of them were discovered in 1860 when the present road to the Citadel was being remodelled. Bell-shaped pits were dug into the bedrock for the storage of cereals or freshwater supply.
Three fairly large silos (approx. 10 meters deep) which are located in this area were originally built for storing grain, but since 1877 they were converted into a water resevoir. Entrance to these siol pits is through the tunnel leading to the Low Battrey, on the left side of the Gunpowder Magazine.
Source: Wirt Ghawdex