SAN DIEGO - The main part of the 44th annual Comic-Con International pop culture extravaganza began Thursday at the San Diego Convention Center, with anniversary tributes for three popular television programs among the day's highlights.
A celebration of the 35th anniversary of "Battlestar Galactica" was one of the first sessions of the conference, with actor Richard Hatch, who played Capt. Apollo, and director Michael Nankin on the panel.
IMAGES: Fun at Comic-Con 2013
TV Guide honored the 20th anniversary of "The X Files," starring Gillian Anderson and David Duchovny as FBI special agents investigating unsolved paranormal cases. The two actors were on hand, as was series creator Chris Carter and several writers and producers.
A forum on the 10th anniversary of AMC's "The Walking Dead" also took place, with series creator Robert Kirkman.
Other actors and actresses making appearances today included Roseanne Barr, Jack Black, Harrison Ford, William Shatner, James Spader and Elijah Wood.
The convention, which runs through Sunday, also offers sessions on writing and comic art, and hordes of attendees will appear in outlandish costumes. The Exhibit Hall is set to open at 9:30 a.m. daily, with the sessions starting at 10 a.m.
Comic-Con began as a small gathering of comic book enthusiasts but has grown over the years to include Hollywood films and television programs. It now attracts 126,000 attendees, the largest annual show at the convention center.
In a statement released early this evening, Mayor Bob Filner said he was dedicated to keeping Comic-Con in San Diego. Cities with larger convention centers have wooed organizers of the event, but San Diego officials hope to break ground on an expansion of the local meeting hall sometime next year.
"I am pleased to announce that I have been working closely with the center's Board of Directors and San Diego business leaders to develop a solid plan for the expansion effort," Filner said. "I support what the board has in mind and will be working with city staff at all levels to ensure we do everything necessary to get the project underway and completed in a timely fashion."
Comic-Con shows the world "how innovation and good ideas can become powerful economic engines," he said.
Prepaid parking at the convention center and Hilton Bayfront Hotel is sold out.
Free shuttles began round-the-clock service at 5 a.m. Thursday and will continue through Sunday at 7 p.m. between the convention center and hotels in downtown San Diego, Mission Valley, Harbor Island and Shelter Island.
Trolley riders can park for free at Qualcomm Stadium. Free trolley parking will also be available on the ground level at Hazard Center Thursday and Friday nights -- and all day Saturday and Sunday.
North County attendees are encouraged to use the North County Transit District's Coaster train.