The central prison of Louvain was built according to the plans of the inspector general of the penitentiary administration at the time, Édouard Ducpétiaux. In 1830, he planned in the center of the country a large prison cell for men sentenced to a long sentence. The prison was put into service on October 1, 1860. It was modelled on the example of the Eastern State Penitentiary begun in Philadelphia in 1822. The original design, by British-born architect John Haviland, was unlike any seen before: seven wings of individual cellblocks radiating from a central hub, according to what became known as the Pennsylvania system, a penal method based on the principle that solitary confinement fosters penitence and encourages reformation, especially by preventing prisoners from encouraging each other in crime. The idea was advocated by the Philadelphia Society for Alleviating the Miseries of Public Prisons, whose most active members were Quakers. The Philadelphia penitentiary opened in 1829, seven years before completion, and proved to be a technological marvel. With central heating, flush toilets, and shower baths in each private cell, the penitentiary boasted luxuries that not even President Andrew Jackson could enjoy at the White House at the time, but prisoners lived in solitary confinement in cells 16 feet high, nearly 12 feet long, and 7.5 feet wide (4.9 by 3.7 by 2.3 m). Separate exercise yards, completely enclosed, were attached to each cell. Prisoners saw no one except institution officers and an occasional visitor. Solitary penitence, however, was soon modified to include the performance of work such as shoemaking or weaving, with a Bible their only possession. They wore hoods all the time they were out of their cells. The Pennsylvania system spread until it predominated in European prisons. Critics in the United States argued that it was too costly and had deleterious effects on the minds of the prisoners. The Pennsylvania system was superseded in the United States by the Auburn system.

Put an end to this hideous form of torture. George F. Will, New York Post (The Week Magazine, 2 March 2013)

"I hold this slow and daily tampering with the mysteries of the brain, to be immeasurably worse than any torture of the body." So declared Charles Dickens in 1842 after visiting a Philadelphia jail that kept inmates in strict solitude. The great author was more right than he knew, says George F. Will. At that time, solitary confinement was still seen as humane reform, promoting reflection and penitence: hence "penitentiaries". But we now know that prolonged isolation does indeed cause lasting brain impairments, leaving many prisoners unfit for normal social interaction. No that this stops the US using it. On the contrary, while it agonises over the ethics of waterboarding ("used on only three suspects" before the practice stopped), it is keeping more prisoners in solitary confinement than ever before: around 100,000 by the latest count. A report on one California prison last year found that 218 inmates had been kept solitary for ten to 20 years; and 90 inmates for 20 years or more. This is both inhumane and counterproductive. Solitary confinement costs about three times as much as normal imprisonment. Worse still, most of these people will one day be back on US streets, "some of them rendered psychotic by what are called correctional institutions".