Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Kronborg Castle' has mentioned 'Fortification' in the following places:
Occurrence Sentence Text Source
In this part, the sound is only 4 kilometres (2.5xc2xa0mi) wide, hence the strategic importance of maintaining a coastal fortification at this location commanding one of the few outlets of the Baltic Sea.
The main architect was the Flemish architect Hans Hendrik van Paesschen and the fortification works were completed in 1577.