The best eco adverts

(CNN) -- If sex still sells, so increasingly does "green". But as consumers we're becoming increasingly savvy to bold-faced greenwashing, so advertisers are being more creative when using environmental themes in their campaigns.

The Cannes Lions 2009 are the advertising world's top international festival. Last month it handed out prizes to a number of agencies that worked on environmental charity campaigns or creatively used environmental themes. From crash test walruses to a scrubbed up San Francisco, take a look at some of the best.

What are your favourite environmental campaigns or adverts? Email us your picks and we'll add them to the gallery.