Oak Island has a secret that it won't give up. The island in Nova Scotia's Mahone Bay is renowned for its "money pit," an excavation that has been the subject of fevered dreams for generations. What, if anything, lies at the bottom of the hole is a mystery, but speculation has ranged from pirate treasure to Peruvian gold to ancient manuscripts. CBC Radio tags along as Texas engineer George Greene takes a crack at the loot.

Since 1795, many people have tried to solve the mystery of Oak Island, and all have failed. The story began when a trio of young men noticed a depression in the ground. Recalling local lore that said pirates had stashed their booty on many of the islands in Mahone Bay, they began to dig. A layer of flagstones gave way to two wood platforms further down, but nothing turned up. Disheartened, the three abandoned the dig.

Nine years later, in 1804, they returned, part of a syndicate formed to retrieve the island's buried secret. Thirty metres down they found a slab carved with unfamiliar symbols and were certain they were close to the treasure. But when they returned the next morning, the shaft was two-thirds full of water — the result of what seems to be an elaborate booby trap designed to keep greedy hands off the prize.

Despite this setback, the lure of instant riches has proven too great to resist. Over the next 150 years numerous searchers, backed by hopeful investors, have sunk many parallel shafts and dug tunnels hoping to solve the mystery. In this 1955 clip, a local man suggests the few tantalizing finds — an old key, some bits of gold chain — were planted by hired men intent on keeping their jobs when their bosses seemed poised to give up.

• Oak Island, named for the trees that once grew on it, was connected to the Nova Scotia mainland by a short causeway in 1965.
• It's unknown whether anyone lived on the island in 1795, but it had already been divided into 32 lots of about 1.6 hectares each. Nobody lives on the island as of 2004.
• The three young men who made the original discovery were Daniel McGinnis, John Smith and Anthony Vaughan.

• The booby trap, whose existence came to light in 1804, was revealed in 1850 to be two intricately engineered tunnels that would flood the main shaft if anyone dug deep enough. The tunnels came from separate sources in Mahone Bay.
• The diggers theorized that the slab covered in strange symbols, which was found in 1804 and later disappeared, was a coded message explaining how to bypass the flood tunnels to retrieve the treasure.

• Drilling in 1850 yielded clues that searchers interpreted as evidence that two wood chests, each full of loose metal, were concealed in the shaft. But the pit collapsed before the flood tunnels could be sealed off and the drilling company, having run out of investors' money, gave up.
• Many more individuals and groups tried to solve the Oak Island mystery. U.S. President Franklin Roosevelt, who had a summer home nearby, expressed an interest but never managed to travel to the island.

• Since 1861 six people have died during excavation efforts on Oak Island. Legend holds that seven must die before the island will give up its secret.
• George Greene, heard in this clip, was bankrolled by Texas oil-company executives. His main achievement was locating a large cavern deep beneath the surface, leading to speculation about natural cavities below the bedrock.
• Greene stayed on the island for just a few weeks in 1955.

• Dan Blankenship was a more persistent treasure-seeker. After reading a 1965 article in Reader's Digest about Oak Island, he travelled there from his home in Florida. He teamed up with David Tobias, a Montreal businessman who had long been interested in the site.
• In 1970 the Triton Alliance, a group of 24 investors including Tobias and Blankenship, put up about $500,000 to continue the search. Among the investors was William Sobey of the East Coast supermarket chain.

• Digging on the island continued into the summer of 2004. The Nova Scotia government granted permission to dig to a company managed by Tobias, but not Blankenship's company. (The pair had parted ways years before.)
• In June 2004 John Wonnacott, an engineer working for Tobias, told CBC's As It Happens about his proposal to use cryogenic freezing to foil the flood-tunnel system.

• In his 1995 book Oak Island Secrets, author Mark Finnan theorized that "something of great value" was concealed on Oak Island sometime between 1545 and 1695. He also wrote that the operation must have been planned by people with "expert knowledge of navigation, mining and marine engineering" who were overseeing "a well-organized, disciplined body of men."
• In 1992 Finnan theorized that the island's treasure could be the original manuscripts of Shakespeare.

• The American magazine Skeptical Inquirer published an article in 2000 doubting whether there was anything of value on Oak Island. Writer Joe Nickell attributed the money pit and underground caverns to natural phenomena.
• Nickell also explained the numerous mysterious discoveries — such as the symbol-inscribed stone — as creations of the Masonic Temple.

Medium: Radio
Program: Canadian Scene
Broadcast Date: Nov. 20, 1955
Reporter: Ken Homer
Guest(s): Ned Fader, George Greene, Cotman Smith
Duration: 11:55