The Rock of Gibraltar was Gibraltar's most famous landmark, which covered most of the territory.
On several occasions, Henry Gordon Jago claimed that he was "as solid as the Rock of Gibraltar". (TV: The Talons of Weng-Chiang; AUDIO: Higson & Quick)
There was a UNIT base under the Rock that was used by Kate Stewart, Josh Carter and Osgood after the Tower of London was destroyed by the Tengobushi. (AUDIO: Ice Station Alpha)