Short answers, pulled from the story.
A prison is a facility where people are imprisoned under the authority of the state, usually as punishment for crimes. It serves two primary functions within the criminal-justice system: holding people charged with crimes while they await trial, and confining those who have pleaded guilty or been convicted to serve their sentences. It can also be used by authoritarian regimes as a tool of political repression.
In American English, a jail holds people for shorter periods, such as less than a year, or for pre-trial detention, and is usually operated by local government, typically the county sheriff. A prison or penitentiary holds people for longer periods and is operated by a state or federal government. After a conviction, a sentenced person is typically sent to prison.
John Howard was one of the most notable early prison reformers who, as high sheriff of Bedfordshire, visited several hundred prisons across Great Britain and Europe and published The State of the Prisons in 1777. He proposed separate cells, professional government-paid staff, outside inspection, and healthy diets. His admirers established the Howard League for Penal Reform in 1866.
In 2021, the World Prison Brief reported that at least 11.5 million people were imprisoned worldwide. In that same year the United States had the world's largest prison population, with over 2 million people in prisons or jails.
The Pennsylvania system, also called the separate system, placed all prisoners in solitary cells with only religious literature and forced complete silence, first used when Pennsylvania turned its Walnut Street jail in Philadelphia into a state prison in 1790. New York later developed the Auburn system, confining prisoners in separate cells but allowing them to eat and work together in silence, used at Auburn State Prison and Sing Sing.
According to the Bureau of Justice Statistics, 67.8% of released prisoners in the United States are rearrested within three years and 76.6% are rearrested within five years. People who have spent time in prison also see their subsequent annual earnings reduced by an average of 52 percent.