The Marvel Cinematic Universe is a colossally ambitious undertaking by President of Production at Marvel Studios, Kevin Feige. Though it began with minor post-credit scenes in films like Iron Man and The Incredible Hulk, it has grown into a recognisable, worldwide brand thanks to the immense smash hits that were The Avengers and Iron Man 3, making it clear that if it continues to be as meticulously preened as it has been to date, the future is very bright for Marvel at the movies indeed. Still, that doesn't stop us from having our fair share of questions about what we've seen so far, and also what's still to come. Some of these questions were no doubt left intentionally ambiguous, whereas others simply require an answer as soon as possible to keep the frustrated fanboys at bay. Here are 10 unanswered questions from the Marvel Cinematic Universe...