Yeah, put me down as curious about the Oak Island thing also.
I think we have a fair handle on the mystery of the "Lost Continent of Atlantis."
The legend pretty much originated with Plato, in his dialogues Timaios and Kritias. According to the story, Atlantis was a large island or small continent whose inhabitants had developed an exceptionally high standard of civilization.
Recent legends (within the past century) have been promulgated by kooks, woo-woos, and outright frauds. One of these was Richard S. Shaver, who wrote bad science fiction and fantasy and tried to peddle it as all true. Things like "The Hollow Earth" (ask your friendly neighborhood astromoner or physicist about bodies the size and mass of the earth possibly being hollow!) and "The Lost Continent of Lemura" (presumed to be like Atlantis, but in the Pacific, and taking the statues on Easter Island as the main evidence for its existence), are all part of this pulp-paper mythology. The legend of Atlantis got a big spurt with this sort of thing. Self-appointed mystics used to make a fair living going around and giving lectures on this stuff, and they drew surprisingly sizable audiences of pretty gullible people.
Actually, if there ever was such a place as Atlantis, it was probably the island of Thera, where there was indeed a highly developed civilization (relative to its times, but they had no special wisdom, nor, for that matter, had they mastered telepathy, levitation, astral projection, or space travel). The civilization came to an abrupt end when Thera, a volcanic island in the Aegean, erupted massively around 1600 BC (made Krakatoa look like a sneeze by comparison), wiped out everybody on the island, dumped ash on the whole eastern Mediterranean, and the resultant seismic sea waves (tsunamis) may have been responsible for legends like Noah's flood, the parting of the reed sea (Red Sea), and a whole bunch of other chronologically scrambled legends. The circular island of Santorini (a caldera) is all that remains of Thera—or Atlantis, if you will.
People quibble that Plato said that Atlantis was beyond the Gates of Hercules, or the Straits of Gibraltar, and that it happened 9,000 years before Plato's time, but others point out that there were places in and around the Aegean Sea that were referred to as "the Gates of Hercules" (there seemed to be no consensus as to where they actually were), and that the Thera eruption took place closer to 900 rather than 9,000 years before Plato's time—possible misplaced decimal. Also, Plato was certainly not an eye-witness to the sinking of Atlantis;he was drawing on legends.
As far as Atlantis being in the Atlantic Ocean somewhere, satellite technology, geodetic surveys, and deep-diving submarines and oceanographic research vessels have covered a lot of pretty soggy territory, discovered the mid-Atlantic ridge, tube worms and other strange life forms living around volcanic "smokers," and a whole bunch of other stuff about the deep oceans, with sunken buildings here and there, but—no sunken continents.