Tasmania - Oatlands Gaol's colonial-era solitary cells unearthed below old pool Archaeologists in a central Tasmanian town have uncovered the footings of colonial-era solitary cells and gallows from the former Oatlands Gaol, which was buried under an old council swimming pool.

The former penitentiary, decommissioned in the 1930s, was once a major correctional facility in Van Diemen's Land. (plus links to related stories)
... The most recent excavation this year uncovered the solitary and condemned cells. (cells were 1 m x 2m - probably built as 1 yard x 2)