Queen Elizabeth I began to transport conflicts to the British colonies in the 16th Century to provide labor to help develop the colonies. In the 17th Century, Europeans began holding in prisons persons convicted as debtors, misdemeanants, and felons. More than half the English prisons at that time were privately operated. They were generally crowded and filthy. Reformers began to seek change during the 19th Century. Many British punishment practices, including capital punishment, were mandated to the colonies. However, Pennsylvania replaced the death penalty with imprisonment. It also developed the concept called penitentiaries, focusing on rehabilitation through isolation and contemplation. New York developed a contrasting facility, the workhouse at Auburn. Both systems used secure facilities made of stone and masonry with high perimeter walls with watchtowers and guards. The industrial revolution brought changes in construction materials and techniques. The expanded role of the labor movement led to restrictions in prison labor. The 1960's brought a renewed focus on rehabilitation and alternatives to incarceration. More recently, new technology has led to innovative structures and security systems. The rising costs of construction will pose a constant challenge to construction. Photographs