The lines seem to have been altered subsequently, as maps from the start of the 18th century show a more erratic course leading from the Landport, Gibraltar's main land entrance, to the Round Tower, a fortification at their western end.

[2] In 1704, an Anglo-Dutch force captured Gibraltar in the name of Charles, Archduke of Austria who claimed the crown of Spain during the War of the Spanish Succession.

[1] During the tenure of William Green as Gibraltar's Senior Engineer from 1761 to 1783, the Lines were repaired, improved and fortified, and the cliffs below were scarped to make them impossible to climb.

[4] Following the Great Siege, the British bored a tunnel called the Hanover Gallery to connect the King's Lines to the Landport near No.

[1] Together with the Landport Front defences, the three sets of Lines constituted such a formidable obstacle that the Spanish called the landward approach to Gibraltar el boca de fuego, the "mouth of fire".

"[6] As John Harris of the Royal Institute of British Architects has put it, they are "capable of providing one of the great architectural experiences in the western world .