The Castle can be visited
Torre Astura
The medieval castle Torre Astura rises on the Tyrrhenian Sea. Located in the municipality of Nettuno in the Lazio region, Italy, it is on a small island connected to the mainland by a bridge.
History+
Already in antiquity, the settlement of Astura was located near the later castle, at the mouth of the river of the same name. During the imperial era, a villa was built on the mainland, whose harbor moles are still visible in the sea today and were likely used until the Middle Ages. In 987, the area was first documented when it was donated to the monastery of Sant'Alessio in Rome. Soon after, the Frangipane family took control, calling themselves Lords of Astura from 1141.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Torre_astura2.JPG
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 41.4079, 12.7649