DOWNTOWN — Comic-Con will celebrate its 40th anniversary as it gets underway today with preview night, officially opens Thursday and runs through July 25. This year’s event at the San Diego Convention Center is a complete sell-out and crowds are expected to be similar to the 126,000 in attendance last year. Costumes and comics will abound at the event that has grown into a pop culture phenomenon since it began in 1970 as only a comic book-centered event. Many film and movie celebrities will be in attendance sharing their stories and taking in the people watching. The event is a place for local comic creators to share their work and an arena for discovery of new books and talent, as many studio representatives are on hand checking out the scene to see what is new. Scheduled events such as “Pokemon” and “Bandai” games draw enthusiasts from across the U.S. The Masquerade is a stage extravaganza of costumes and will be presented by HBO’s “True Blood” this year, taking place on Saturday. An audience of 4,200 will fill the Convention Center’s ballroom to capacity, while others will watch the show on video screens throughout the building. For more information and to see the list of special guests visit www.comic-con.org.