A close up of the jail

Originally the island was used as a fortress as a natural defence point to defend the Golden Gate entrance c 1852. The original island slopes were smooth but you can see where they have been dynamited in order to create a more defendable position.

When it's fortress needs lapsed it was used as a military minimum security prison, mostly for deserters. Little baracading was used as the strong currents and distance from the shore line deterred most occupants. Rumours of sharks also kept in mates on the island. There are no sharks naturally in these waters but it is said that some were shipped in just so that the in-mates could see the odd shark fin.

It only became a state maximum security prison in the 30s to hold the likes of Al Capone who kept their criminal activities going whilst housed in other prisons. It ended it's use as a prison in 1963 and eventually became a museum in the early 1970s after a short period as a hippy commune.