Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Natural and Culturo-Historical Region of Kotor' has mentioned 'Fortifications' in the following places:
Occurrence Sentence Text Source
The fortifications consist of a system of defensive military buildings to protect the medieval town of Kotor.
While some of the structures date back to Roman and Byzantine times, most of the fortifications were erected during the Venetian rule; later some modifications were made by the Austrians.
The fortifications are the most significant aspect of the World Heritage site.