Conciergerie Prison (La Conciergerie), located on the Île de la Cité in Paris, served as a royal palace before its conversion into one of the most notorious prisons during the French Revolution. The transformation of the Conciergerie from a palace to a detention facility began in the late 14th century. However, its role became particularly significant during the Reign of Terror (5 September 1793 – 28 July 1794), when the Revolutionary Tribunal used it to detain individuals accused of anti-revolutionary activities. The prison's proximity to the Palais de Justice (the courthouse) made it an ideal holding site for those awaiting trial or execution. The Revolutionary Tribunal, established by the National Convention to try enemies of the revolution, was housed within the Conciergerie. This tribunal was notorious for the speed and severity of its judgments, often leading to harsh sentences with minimal evidence. The Conciergerie was overcrowded and unsanitary. It typically housed prisoners in cramped cells, with little regard for hygiene or comfort. Aristocrats, political prisoners, and ordinary citizens alike were held in the same dreary environment. Among the most famous inmates was Queen Marie Antoinette, who was transferred to the Conciergerie in August 1793 before her trial and subsequent execution on 16 October 1793. Her cell (a sparse, heavily guarded room) has since become a symbol of her tragic end. During the Reign of Terror, thousands of prisoners passed through the Conciergerie. Many were sent to the guillotine, which was located a short distance away at the Place de la Révolution (now Place de la Concorde). Public executions became a common spectacle, contributing to the prison's fearsome reputation. Robespierre, a leading figure in the revolution and head of the Committee of Public Safety, also spent his final days at the Conciergerie after his arrest on 27 July 1794. On 28 July 1794, he faced the guillotine, marking the end of the Reign of Terror and highlighting the prison's role in the cyclical nature of revolutionary justice. Robespierre's detention underscored the unpredictability and breadth of the revolution's reach, as former revolutionaries themselves became victims. After the fall of Robespierre, the use of the Conciergerie decreased, and the prison's role evolved. Despite its grim past, today the Conciergerie stands as a museum and historical site, offering insights into the revolutionary period of French history. The cells and briefing rooms have been preserved, providing visitors with a tangible connection to the events and individuals that shaped the course of the French Revolution.