Superman and Batman on the same stage, a Star Wars cast reunion and a Bryan Cranston clanger that threatened to bring proceedings skidding to a halt. After four and a half days of toys, fanboys, cosplay and the clink of coins, the annual geekfest Comic-Con has drawn to a close.

With a handful of major movie titles - notably Batman vs Superman and Star Wars: The Force Awakens - vying for buzz, plus a slew of new TV shows including Supergirl and Lucifer, this was a convention for the young, and the young at heart.

Without a doubt the highlight was the surprise symphony concert sprung on Star Wars fans by director J.J. Abrams who, at the conclusion of The Force Awakens panel in the San Diego Convention Center's cavernous Hall H, invited everyone to a concert.

The halls doors creaked open and a legion of uniformed Imperial stormtroopers escorted the crowd of more than 6000 fans from the convention center to an outdoor stage where the San Diego Symphony Orchestra performed a recital of the original Star Wars soundtrack.

And that was just the icing on a cake which included an on-stage reunion between the stars of the original Star Wars trilogy, Mark Hamill, Carrie Fisher and Harrison Ford.

"It was like a flashback," Fisher said, of filming Star Wars: The Force Awakens. The same could be said of Comic-Con.

Meanwhile, actor Bryan Cranston very nearly stole the show on the fourth day of the convention, appearing on a panel at one of the satellite venues, the appropriately named NerdHQ.

Asked by fan what he did in his spare time in Albuquerque, New Nexico, during the filming of the critically acclaimed television series Breaking Bad, Cranston answered provocatively: "Yeah, I'd go and visit your mother once in a while."

Cranston then deliberately dropped his microphone and the crowd erupted into applause. Comic-Con will close its doors today having pushed almost 150,000 fans through its doors across four and a half days of show launches, screenings, panels and publicity stunts.

Even in its final hours, the convention centre floor is packed with fans scouring the aisles for hidden gems, old comic books, old Lego kits and action figures, and all manner of the strange and sundry.

For the last week the streets of San Diego's "gaslamp" old town district have been packed with a mixture of revellers, convention-goers and fans dressed as everything from stormtoopers and superheroes, to Lily Munster and all manner of undead, but most notably zombies.

Though it was born as a bona fide comic book convention in 1970 - a pastime which still commands a chunk of the convention floorspace to this day - Comic-Con has become one of the most important dates on the film and television marketing calendar.

The convention was also packed with Australians, ranging from those with something to sell - such as Luke Mitchell, who stars in Marvel's Agents of Shield, and Travis Fimmel, from Vikings, to Emilie de Ravin and Georgina Haig, who both appear in Once Upon A Time.

There were also some surprises, including an appearance by Margot Robbie and Jai Courtney and other stars from Warner Bros upcoming comic book blockbuster Suicide Squad, and Hugh Jackman, who is starring in Pan.

The marketing machinery of the Hollywood studios also saw celebrities and media pushed through a dense social calendar, with exclusive parties dotted across the city.

The hottest tickets included Warner Bros' party at the Hard Rock's Float Bar, with a guest list of Warner studio stars and even the iconic Lee Meriwether, who played Catwoman in the 1960s, and the BBC's party at Omnia, which featured the stars of Doctor Who, including actors Peter Capaldi and Michelle Gomez.

Planning for the convention this year had a shadow of uncertainty hanging over it: no firm agreement in place to keep it in San Diego; that changed last week when the city's major confirmed it would remain here until at least 2018.

Among the key issues were the city's hotel room capacity in the face of ever-increasing crowds drawn to the event, and a concern that if the flagship Comic-Con event were moved to another city, another convention operator would shift a similar convention into the space.