Monte Guardia is the highest peak on the island of Ponza, measuring more than 900 feet (280 meters) in altitude.

Travelers to the island will spot a lonely ruin at the top of the peak that hearkens back to a forgotten form of technology used for communication.

Il Semaforo was constructed during the 1800s around an older watchtower from the 1600-1700s. Nautical maps from the period label the site as the "telegraph." At the time, an engineer by the name of Claude Chappe developed an early type of telegraphy, the semaphore system, which helped establish later electric telegraphy. 

Beacons, such as the one on Monte Guardia, consisted of masts with two cross-arms on pivots that could be moved into different positions, each corresponding to a specific code. Operators from other beacons and towers could transcribe the message by observing the positions of the masts with spyglasses. Of course, this system depended on good weather and daylight. Eventually, electric telegraphy replaced Chappe's invention.

The spectacular lighthouse, Faro della Guardia was constructed on the rocky outcrop just below Monte Guardia. When warfare broke out in the region, defensive structures composed of cement were constructed around the Semaforo. However, the site was progressively abandoned during the 1950s. Now, it's in a ruinous state and is fenced off.