Château de Montlhéry

Chateau de Montlhery is a medieval fortress with five defensive towers arranged in a pentagon shape that dominates the Ile-de-France landscape. The central keep rises above the outer walls and forms the strongest point of the structure.

The castle was built in the early 1000s and later rebuilt in the 13th century under Philip II Augustus after King Louis VI destroyed it. These reconstructions made it one of the region's most important fortresses.

The castle was home to a powerful family whose influence shaped the region for centuries. Visitors today can see traces of this importance in the surviving structures.

The grounds are open to visitors and allow exploration of the central keep and the medieval well. The paths along the preserved walls are walkable but offer limited shelter and can become slippery in bad weather.

In the 17th century, scientists such as Pierre Gassendi used the tall keep for optical and mathematical experiments. These studies contributed to important discoveries in astronomy and natural science.