People have speculated over the dates Atlantis sank for years.   If you favor the Mediterranean version of Atlantis, you have one date.  If you favor something something in the Atlantic near Bimini, you typically favor an older date.   I tend to lean towards the later.

Many people believe that the sinking of Atlantis coincided with the subsequent rise of Egyptian culture.  Based on the research by Robert Schoch into weathering around the Sphinx, the pyramids should be around 10,000 years old.   The following video makes an interesting case.  I haven’t figured out if the location makes perfect sense or it makes no sense at all.  This is based on an inscription inside one of the air shafts.  It’s 10 inches wide and if it weren’t for a robotic camera, no one would ever see this.  It has the ring of a carpenters mark, but it also seems to say, this is when I finished.  The two seem somewhat contradictory, since the first is almost always hidden (which this is), and the later is usually displayed for people to see.  Assuming it is what it appears to be, we would have to assume that the builder was aware of star procession to the point that leaving this mark would have meaning in a few thousand years.