This image was found by aeronautical engineer Bernie Bamford as he browsed through Google Ocean. This could be the remnants of a city, possibly Atlantis, or just an incredibly linear natural formation. Time will tell, but it is a very interesting find.
If you find the site on Google Earth, just northwest of the Canary Islands, you can see more linear lines to the east of the site.
Update: I have heard the theory that the above picture is simply a satellite mapping artifact, similar to the lines seen off the coast of Los Angeles in Google Earth.