Just outside Belmonte in a small place called Colmeal da Torre, stands an enigmatic tower that has been around since the 1st-century CE.

Driving on the N18 road going south, almost arriving at Belmonte, visitors are greeted by an eerie tower standing in the distance to the far left. The building resembles an old crown made of stone, haunted by flocks of birds that fly around the building and nest in the crevices of the rocks. There is a spooky feeling once visitors step inside the tower.

The tower is believed to be a Roman villa known as Villa of a Lúcio Cecílio and belonged to a tradesman of one of the richest ore-producing areas in the Roman empire.

However, there are other theories as to its existence. One theory suggests the structure was a jail with 100 cells, hence the name "Centum Cellas," where Saint Cornélio was allegedly imprisoned. It's also believed by some that the building may have been a Roman camping ground for the military. Archeologic work during the 1960s and the 1990s suggests it was actually just a villa. 

The tower is rectangular and about 39 feet (12 meters) high with no roof or floors. There are also several windows around the building. The site is gated but there is no entrance fee (there are two open gates). There is ongoing archeological work at the site, but visitors can step inside the tower.