At the southern tip of Spain, jutting out into the Mediterranean Sea, lies Gibraltar, a narrow peninsula measuring only 6.8 square kilometres or 2.6 square miles in area and dominated by a 426 metre or 1,298 foot high limestone monolith: the legendary Rock of Gibraltar. A British overseas territory and naval base since 1713, Gibraltar has long been of vital strategic importance, controlling the narrow passage between the Mediterranean and the Atlantic Ocean. And at no time was this truer than during the Second World War, when the Axis powers plotted to capture Gibraltar in a bid to cut Britain off from its overseas Empire and starve her into submission. And though the heavily-defended enclave would be a tough nut to crack, the very real threat of invasion led British military planners to take elaborate precautions should the“Rock” ever fall. And perhaps the most extreme of these contingencies was an utterly bonkers plan to seal six men into a secret network of tunnels and chambers carved into the Rock of Gibraltar. Provided with several years’ worth of food and water, these volunteers were to spy on the occupying Axis forces and report their movements back to Britain, secretly keeping Gibraltar in the fight. This is the bizarre tale of Operation Tracer. What is now known as the Rock of Gibraltar was formed during the early Pliocene Epoch around 5 million years ago, when the collision of the African and Eurasian tectonic plates lifted up and inverted a large slab of the Eurasian plate, composed of the 200-million-year-old Catalan Bay Shale, Gibraltar Limestone, Little Bay Shale, and Dockyard Shale formations. The ongoing movement of these plates continues to push the Rock of Gibraltar steadily skyward, with the monolith growing in height at a rate of around 0.05 millimetres or 0.002 inches per year. The area has been inhabited for at least 125,000 years, with the bones, tools, and other remnants of both neanderthals and modern Homo sapiens being found in numerous caves dotting the peninsula. In antiquity the Rock of Gibraltar, then known as Mons Calpe, was frequently visited by Phoenician, Greek, and Roman mariners, with the Greeks recognizing the mountain as one of the two “Pillars of Heracles.” According to Greek mythology, while trying to obtain the Cattle of Geryon - the 10th of his 12 Labours - the legendary hero smashed his way through the Atlas Mountains, forming the Straits of Gibraltar and connecting the Atlantic Ocean and Mediterranean Sea. The identity of the other pillar has been lost to history and is heavily debated among classicists, though it is now widely believed to be either Monte Hacho or Jebel Musa in Morocco.... Author: Gilles Messier Editor: Daven Hiskey Host: Daven Hiskey Producer: Samuel Avila Learn more about your ad choices. Visit megaphone.fm/adchoices