Zombies are the monsters of the 21st century, and America's major contribution to horror. What set off zombie fever? All roads lead to George Romero, who made zombies a metaphor for social ills.

Ghost movies have been with us since the dawn of cinema. Some ghosts are benevolent, some ghosts are malicious, but they all represent the mystery of what happens to us after we die. Stephen King, Haley Joel Osment and others break down the appeal of spooky spirits.

The history of monster movies is also the history of the evolution of special effects technology; whatever their size or shape and whatever they represent, for many horror fans monsters are the best part of the genre.

Fans of horror films, like "A Nightmare on Elm Street 3," "Psycho II," "The First Purge," "Bride of Chucky," "Scream 2" and "Gremlins 2: The New Batch," say sometimes sequels are as good or even better than the originals.