The gentleman who narrates this video, Graham Hancock is extremely controversial.  Some think he is off base in all his theories while some think he is visionary.  Here are some of the contradicting comments:

Commenter dinomand is a skeptic:

“To bad that this guy is so poor at real science. Think what he could do if he actually used critical thinking and evidence, instead of wishfull thinking and clear byas towards fringe interpretations.”

Commenter jack K is more in the camp of thinking there is something of value here:

“Fantastic. Thank you for taking the time to present this to us. I think it would really depend on the rock. Those big monolithic rocks, that whole structure, doesn’t look like the type to break off in a perfect angle repeatedly, versus other rocks, that do brake, that are softer. After all they’re form is still there thousands of years later. I like the “harbor” idea. Looking forward to your next adventure.”

If nothing else this is interesting and feel free to comment with your theories or opinions!