The famed White Cliffs of Dover really are white. In 1991, we took the SeaCat from Dover to France. As soon at you get out of the docks you can look back and see the white cliffs. Here's Windows Live Local's Bird's eye view. Here's the wikipedia article.
Be sure and pan slightly to the southwest to see the docks for the channel ferries. Here's my picture taken off the back of the SeaCat.
Here's one of the channel ferries in the open sea.