Comic-Con, an annual comic convention in San Diego is in full swing, and every year Marvel cleverly leverage the event to showcase and promote their upcoming films in order to build anticipation, and give die hard fans an insight into what to expect from potential blockbusters.

This year's no different. Fans were given a sneak peek into character profiles of Bryan Singer's huge multistarrer X-Men Days of Future Past, but what was even more exciting was a look at the design of a Sentinel head. For those of you that aren't familiar with the comics, Sentinels played a huge part in the X-Men series. Essentially, they're huge robots commissioned and programmed to capture, and in some cases, destroy mutants.

We have a shot of the head for you right here (courtesy Screen Crush), and we even have some key character portraits courtesy Geek Tyrant. 

Early posters: X-Men Days of Future Past

We've also included other shots that Bryan Singer has tweeted over the past few months, and our initial expectations from this film are that it may even go on to destroy the records set by Avengers Assemble last year. 

X-Men Days of Future Past stars Ian McKellen, Hugh Jackman, Patrick Stewart, James McAvoy, Michael Fassbender, Jennifer Lawrence, Nicholas Hoult, Anna Paquin, Ellen Page, Shawn Ashmore, Omar Sy, Halle Berry, Daniel Cudmore, Fan Bingbing, Evan Peters, Josh Helman,and Boo Boo Stewart and releases 23 May 2014.

Gallery: X-Men Days of Future Past