Montlhéry Castle is a medieval fortress located in the town of Montlhéry, France. Built in the 10th century, it was strategically positioned on a hill to oversee the surrounding area. The castle features a unique circular keep and impressive defensive walls, showcasing the architectural style of its time. Throughout its history, Montlhéry Castle has witnessed numerous battles and sieges, reflecting the turbulent nature of medieval France. It was an important stronghold for various noble families and played a significant role during the Hundred Years' War. Today, the ruins of the castle are a popular site for visitors interested in history and architecture.