Okay i'll bite - what does a fiction story (Da vinci code) have to do with Oak lsland?

the posibility that the Templars/masons hid their treasure there after being forced to move it from Scotland, after being ran out of france.

It is very interesting how there is a "treasure" that keeps showing up, in ever more remote locations as the 18th-19th centuries pass.
1st you have oak island, where a treasure was suposedly hidden in a impossibly complex tunnel system.

Then there are the tales of "spanish" gold that come out of the american south west.

Then there is the story of the guy in the 1920's who found a cache of gold and jewels in the deserts of nevada.
He actually spent some of the loot in vegas gambling. There was one peice he recovered, a broach I think it was, that was photographed, and identified.
It was a known piece of jewelry from a European Royal house's Crown jewels, I think french, and hadnt been seen in a couple of centuries.
He kept the treasures location secret and took it to his grave so to speak.
He died from injuries in a fall while working the site. His wife and children helped him at the site, but he always blindfolded them when driving out to it, so they could not find the site after he died.


Then there were the 2 airforce enlistees, who were hiking in a restricted part of White sands missle test range, and found a cave filled with chests of gold and jewels. There were several rooms with stuff including art work and armor, real old world stuff.
They kept it a secret till they retired, then sued the airforce to get permission to go looking for it, but when they were finally given permission to look, guess what it wasnt there anymore.
Imagine that.

Personaly I think Oak island was the repository for the royal army's cash supplies during the revolution. The Royal Engineers wold have had the skills and resources needed to complete the task.