Perched atop a 30-meter-high hill, the Montlhéry Tower offers a breathtaking panoramic view of Essonne and the Île-de-France region. This historic medieval relic, officially listed as a Monument Historique, once served as a laboratory for some of the greatest scientists of the 19th century. Whether you're interested in its history, planning a visit, or just taking a leisurely walk, here's everything you need to know.