OK. Here's some google stuff:

This monument, situated just passing the control post in Gibraltar's Upper Rock Nature Reserve, looks out over Europa Point, the Mosque and the Lighthouse.

The plaque reads "To the ancient world, Gibraltar was known as Mons Calpe, one of the legendary pillars created by Hercules as a religious shrine and as an entrance to the Mediterranean. To many it signified the non plus ultra, the end of the then known world".


http://www.gibnet.gi/~dparody/gibmap/pillars.htm

So that's one of the pillars, huh? How many pillars did Hercules build? The ones shown in the picture on the above url look like Corinthian columns to me. Please correct me if I'm in error here.

wwh, I gotta go look at my mother's daylilies, but I promise I'll research this subject more deeply on google later.