703 Fifth Ave., New York CityFour lucky couples who won a Colin Cowie Weddings contest not only got to utter “I do” at that most romantic of locations—on top of the Empire State Building—on that most romantic of days, Valentine’s Day—they also got to seal the deal with custom-designed, Facebook-approved diamond wedding bling from De Beers. The couples first got to see their rings at a champagne cocktail event at De Beers’ New York City flagship on Feb. 10. Getting involved in the contest was “very organic, very natural,” says Selda Bensusan, De Beers director of public relations and special events. “We are all about love, so it was a perfect match.”Taking WingsMatthew CarasellaThe winners of the “Wings of Love” contest were chosen from across the country after sending videos to Cowie describing their love stories. (At least one was recorded in De Beers’ New Yo