The « Pontons », floating prisons in Brest harbour

“Pontons”: in the 19th century, this french term referred to disused ships housing prisoners. In other words, floating prisons.
In 1871, in Brest harbor, a large “fleet” of 11 stationary ships housed almost 12,000 prisoners. 171 of them perished, while the rest were shipped to New Caledonia or Algeria.