This year’s Comic-Con International: San Diego takes place in southern California from 19-22 July.

The biggest entertainment expo in the world, Comic-Con has grown from humble origins to become one of the most influential pop culture events in the calendar, attracting large crowds, panels of A-list franchise stars and exclusive trailer premieres.

An opportunity for fans to meet their heroes, score autographs, buy collectibles, dress up and interact with fellow enthusiasts – no matter how niche the shared obsession – Comic-Con is now in its 48th year and going from strength to strength.

This is in no small part thanks to the boom in interest in CGI superhero blockbusters since the turn of the millennium and the emergence of Marvel as a Hollywood power player.

Comic books and genre fare have joined the mainstream since the dawn of the internet and Comic-Con's sprawl perfectly represents the opening out of the culture.

The inaugural event, held on 21 March 1970, was known as Golden State Comic-Minicon and held at downtown San Diego’s US Grant Hotel. It was masterminded by fanboys Shel Dorf, Richard Alf, Ken Krueger, Mike Towry, Barry Alfonso, Bob Sourk and Greg Bear, who hoped to attract enough fans to stage a more ambitious convention later that summer.

They succeeded. While 100 people attended the first, 300 came to the second, with legendary illustrator Jack Kirby and science fiction novelist Ray Bradbury among the invited guests and the events offered including discussion panels, a dealers’ room and film screenings.

Kirby advised the organisers not to restrict themselves solely to comic books and make the conference multimedia, taking in sci fi and fantasy novels, genre films and television – a sound suggestion that gave the convention room to expand into emerging new areas like video games and draw from a much wider pool of fans, appealing to lovers of anime and horror alike.

Swiftly becoming an annual fixture, Comic-Con moved to the El Cortez Hotel and the Convention and Performing Arts Centre, before finally shifting to the city’s labyrinthine Convention Centre where it has been held every year since 1991.

Today, the event typically attracts crowds of around 130,000, many of whom take part in cosplay – a Japanese import that has become a signature of Comic-Con.

Popular costume options at 2017’s conference included: Deadpool, Wonder Woman, The Joker and Harley Quinn, Dr Strange, Beetlejuice, Moana, Ghost Rider, Lando Calrissian, Gomez and Morticia Addams, Shredder and Krang, the Demogorgon and “Make the Empire Great Again” Storm Troopers with Donald Trump hair.

Revellers brave the sweltering summer heat to pose for pictures in costumes that are cheered for their ingenuity, effort and attention to detail, the best invited to take part in a ticketed catwalk “masquerade” to model their outfits.

David Schoelen poses as the Demogorgon from 'Stranger Things' during the 2017 Comic-Con International Convention in San Diego, California (Mario Anzuoni/Reuters)

Comic-Con has been praised for the atmosphere of friendly inclusivity it fosters but those less enamoured have satirised it as “Line-Con”, a complaint about the amount of queueing required for everything from fast food to signings to entry to the hallowed Hall H, where Henry Cavill and company hold court.

Like Glastonbury, Coachella or SXSW, the massive commercialisation of Comic-Con has also attracted criticism.

Comics publisher Mile High announced they would no longer attend in 2017 after 44 years due to the rise in the cost of a booth, stating in a blog post that the price of reserving one had ballooned from $40 in 1973 ($232 or £176 today) to $18,000 (£13,655).

In pictures: Comic-Con 2015 Show all 30 1 /30 In pictures: Comic-Con 2015 In pictures: Comic-Con 2015 Comic-Con 2015 Co-hosts/actors Bella Thorne (L) and Tyler Posey perform onstage during the MTV Fandom Fest San Diego Comic-Con at PETCO Park In pictures: Comic-Con 2015 Comic-Con 2015 Executive producer/creator Bryan Fuller waves as he arrives at the 'Hannibal' Savor the Hunt panel during Comic-Con International 2015 Getty Images In pictures: Comic-Con 2015 Comic-Con 2015 Actor Ron Perlman poses for a portrait with Ron Perlman impersonators at Comic-Con International 2015 in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Cosplay enthusiasts Jonathan Michael (L) and Connor Breen are dressed like the Mad Hatter from "Alice in Wonderland" during the 2015 Comic-Con International Convention in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Guests attend the Dragon Ball Z: Resurrection 'F' San Diego Comic-Con opening night VIP party held at Whiskey Girl in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Actor Denis Leary speaks on stage at the FX TV Block featuring 'Sex&Drugs&Rock&Roll,' 'The Strain,' and a sneak peek of 'The Bastard Executioner' panel during Comic-Con International 2015 Getty Images In pictures: Comic-Con 2015 Comic-Con 2015 Actor Greg Grunberg (left) and writer/producer Tim Kring take a selfie on stage at the 'Heroes Reborn' exclusive extended trailer and panel during Comic-Con International 2015 Getty Images In pictures: Comic-Con 2015 Comic-Con 2015 Actress Lea Michele walks onstage at the 'American Horror Story' and 'Scream Queens' panel during Comic-Con International 2015 Getty Images In pictures: Comic-Con 2015 Comic-Con 2015 Actresses Emma Roberts (L) and Lea Michele of the show 'Scream Queens' visit the Scream Queens Mega Drop Ride during Comic-Con International 2015 Getty Images In pictures: Comic-Con 2015 Comic-Con 2015 (L-R) Actors Liam Hemsworth, Josh Hutcherson, Jennifer Lawrence and director Francis Lawrence of "The Hunger Games: Mockingjay - Part 2" attends the Lionsgate press room during Comic-Con International 2015 at the Hilton Bayfront in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Actor Jeffrey Dean Morgan and actress Halle Berry speak onstage during CBS TV Studios' panel for "Extant" during Comic-Con International 2015 at the San Diego Convention Center In pictures: Comic-Con 2015 Comic-Con 2015 Cosplayers pose for pictures while a picketer holds a pro-religion sign outside of the Convention Center at the 2015 Comic-Con International in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Brandon Moriesta (R) interacts with a Cosplay character at the 2015 Comic-Con International in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 A group of Power Rangers pose inside the Convnetion Center at the 2015 Comic-Con International in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 A person who goes by the name of Nomad poses for a photo during the 2015 Comic-Con International Convention in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Lee Shannon, dressed as Ming the Merciless, and his girlfriend Kira Krend, of Kaneohe, Hawaii, chat on the escalator at Comic-Con International in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Fans wear costumes at the convention center on opening day of the 2015 Comic-Con International in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Attendee Jerry Lee holds up his baby Dylan Lee, seven months, between Lego figures of Iron Man and The Hulk at Comic Con International in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Dustin Agosta, whose drag name is Discord Adams, is dressed as a drag Joker at Comic Con International in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Young attendees look at a figure of a zombie from "The Walking Dead" television show at Comic Con International in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Ayelet Bick takes a photograph of herself next to a Star Wars figureat Comic-Con 2015 in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Super heroes on display at the Comic-Con in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 An attendee dressed in cosplay as the character Ash from the movie "The Evil Dead" outside the 2015 Comic-Con International in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Ronnie Nadal poses for a photograph with his two daughters, Kalissa, 9, and Kailah, 6, at Comic-Con 2015 in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 Sabastian and Julia Sanzberro, dressed as Fred Flinstone and Barney Rubble, walk the trade floor at the 2015 Comic-Con International in San Diego In pictures: Comic-Con 2015 Comic-Con 2015 People dressed as sharks dance outside the San Diego Convention In pictures: Comic-Con 2015 Comic-Con 2015 Participants dressed in Zombie outfits walk down the Gaslamp Quarter outside of the 2015 Comic-Con International in San Diego, In pictures: Comic-Con 2015 Comic-Con 2015 A dressed participant at Comic-Con International in San Diego Convention Center In pictures: Comic-Con 2015 Comic-Con 2015 Dressed participants at Comic-Con International in San Diego Convention Center In pictures: Comic-Con 2015 Comic-Con 2015 Participants pose for the photograph at the Comic-Con International 2015 in San Diego

The cost of attending Comic-Con is high, especially when the price of hotel rooms and parking (up to $50 a night) is factored in with the price of tickets: $63 (£48) a day for adults, $31 (£24) for under-17s on the busy Thursday, Friday and Saturday instalments.