I thought everyone knew that you can’t qualify “unique.” Something is unique or it’s not – simple as that. And yet, in a Jan. 8, 2011, piece in the New York Times, Neil MacFarquhar writes, “Here in Djenné, the striking Great Mosque is what put the town on the map. It is the largest mud-brick structure in the world, so unique that it looks as if it might have landed from another planet. . . ”
Just in case they update this article, here’s a screen shot of this grammatical infraction, captured Sunday afternoon, Jan. 9, 2011:

As this online grammar guide suggests, “unusual” might have been a better word choice.