Ghosts of the Abyss (Blu-ray release 2012-9-11) is James Cameron’s documentary of his team’s expedition to the wreck of Titanic in 2001.  It brings fascinating footage of the remains of the Titanic sitting in the bottom of the ocean.  It frequently overlays CG on top of actual footage to help the audience see exactly what is being shown.  This is a fine documentary, but I imagine only people who are interested in Titanic or the 1997 movie will watch this.  Note: the 91-minute extended version is only available on the 2D disc, not on the 3D disc (which contains the theatrical version).