Prince's Lines - Credit: Wikimedia Commons
The Prince's Lines are part of the fortifications of Gibraltar, situated on the lower slopes of the north-west face of the Rock of Gibraltar. They are located at a height of about on a natural ledge above the Queen's Lines, overlooking the landward entrance to Gibraltar, and run from a natural fault called the Orillon to a cliff at the southern end of the isthmus linking Gibraltar with Spain.Hughes & Migos, p. 335 The lines face out across the modern Laguna Estate, which stands on the site of the Inundation, an artificial lake created to obstruct landward access to Gibraltar. They were constructed to enfilade attackers approaching Gibraltar's Landport Front from the landward direction.Cornwell, p. 15 Read more on Wikipedia
Source: en.wikipedia.org