Break out the tights, the countdown to America's biggest Comic-Con is underway.

The four-day extravaganza is expected to bring nearly 130,000 people, $166 million in revenue, and just over $2.5 million in tax revenue into San Diego this year.  

The annual event has also turned into a tremendous opportunity for Hollywood to promote current and upcoming films and TV series, with exclusive footage and appearances by big-name actors.  

Everything gets started tomorrow night with a special sneak preview, while the main event gets underway Thursday morning.