[dtegart]

The entire Rock of Gibraltar was turned into a fortress during the war. The civilian population was evacuated, and additional tunnels and artillery placed in the rock. I am not sure that the German siege weapons could have reduced a block of granite into rubble.

[Tuna-Fish]

With sufficient heavy artillery, while you might not be able to breach into the fortifications, you can certainly mess it up enough to stop it from shooting back.

It would not have been necessary to actually take Gibraltar -- only to silence it's guns, and place enough artillery west of it to block the strait.