Romance is a genre that remains timeless, its films providing many of the most memorable moments in film history. Ask someone who her favorite onscreen couples are and she will likely mention Vivian Leigh and Clark Gable in Gone with the Wind, Ingrid Bergman and Humphrey Bogart in Casablanca, Julie Christie and Omar Sharif in Dr. Zhivago, and Audrey Hepburn and Gregory Peck in Roman Holiday. The romance genre can be funny, tragic, ridiculous, ironic, or gut-wrenching, and can span all levels of passion in both the real world and otherworldly environments.

Romance is an easy choice for crossing over almost all genre lines. Romantic comedies in particular haven't lost their appeal over the decades. From Bringing Up Baby to Sleepless in Seattle, audiences continue to love a happy ending — especially if the road is paved with humor. The same goes for many of the other romantic subgenres, which include:

• Romantic Comedy (It Happened One Night, The Philadelphia Story, Annie Hall, When Harry Met Sally, Roxanne, My Man Godfrey, Ninotchka, Some Like It Hot, Desk Set)

• Dark Romance (War of the Roses, Body Heat, Anna Karenina, A Place in the Sun, Bram Stoker's Dracula, Rebecca)

• Classic Romance (African Queen, Sense and Sensibility, Out of Africa, The Way We Were, The Thin Man, Breakfast at Tiffany's, Sabrina, Pillow Talk, The King and I)

• Supernatural Romance (The Ghost and Mrs. Muir; Ghost; Truly, Madly Deeply; Somewhere in Time; Heaven Can Wait; The Bishop's Wife)

• Historical Romance (Wuthering Heights, Dr. Zhivago, A Room with a View, Dangerous Liaisons, The Unbearable Lightness of Being, Last of the Mohicans, Pride and Prejudice)

• Love under Adversity (An Affair to Remember, Moonstruck, Titanic, Pretty Woman, Witness, Coming Home, The Bridges of Madison County, The Crying Game)

• Fantasy Romance (An American in Paris, Gigi, The Princess Bride, Lady and the Tramp, The French Lieutenant's Woman)

• Romance Gone Bad (Double Indemnity, Niagara, The Postman Always Rings Twice, Damage, Fatal Attraction, Disclosure, Revenge)

As are romances in life, romance movies are anything but predictable. More often than not, the key to a successful romance is the strength of a screenplay and the charisma of actors involved in the production. Always remember that if you're going to play the love game, romance in film is part intuition, part execution, but almost entirely chemistry.