Arco di Trevi

Pilgrims walking the way of Saint Benedict or hikers exploring the regional park of the Simbruini Mountains, the largest protected area in the Italian region of Lazio, will stumble upon this ancient stone arch hidden in the forest.

Archaeologists date this monument to the pre-Roman period, however, it's uncertain whether the structure was constructed by Romans or local tribes. The massive arch has been dated to the 3rd or 4th century BC. The exact purpose of the structure or what it belonged to is still a mystery. 

Some researchers believe it may have supported an ancient aqueduct, others think it was a checkpoint of sorts along the pastoralist/transhumance routes of the Appennines. It does appear to have been strategically constrcuted along the borders of the former Equi and Ernici territories.

The arch is made of heavy squared blocks of limestone set against each other without the use of mortar. It stands nearly 20 feet (six meters) tall and 13 feet (four meters) wide.