With its majestic size, and being 1669 meters above sea level, overlooking the entire Valley of the Liri-Garigliano Rapido, it is visible from everywhere, with its colour between blue and green, depending on the distance from which it is observed. To arrive, the trails of Monte Cairo are easy to navigate. Monte Cairo belongs to the Meta and Mainarde groups, but has its own stand-alone configuration. The name comes from the Latin 'clarus' (light), perhaps because of its particular exposure and the constant lighting of the sun. During the Middle Ages it was also called Kareah. The castle was protected by five towers, one with a predominant function of defense and the other four, one for each side of the complex mainly as watch towers and for internal and external communication. Today only the outer walls of the castle and corner towers remain.