Well - as most will know I've maintained that it would be little more than a patch of dark sand, a larger version of a few dark patches we saw to the north of Larrys Lookout.

It's been 'properly' named El Dorado as a nod to the online MER community that was obsessed with the place for the better part of a year.

We're approaching from the east of it, and should actually be right on top of it within a few sols,
http://marsrovers.jpl.nasa.gov/mission/tm-spirit/index.html

We are in fact much closer than that, about 2 50m drives have put us about 50m from the dunes themselves.

Whilst we've not seen a picture showing the centre of the patch, we're seing quite a lot of imagery of it from the 'side'

These three images, from yestersol, show it farily clearly