10 Obscure MCU Movie Secrets That Took Years To Discover

And we conclude our list on perhaps the finest secret of the lot, quite aptly hidden within the movie that started it all - 2008's original Iron Man.

You may remember the scene in which villain Obadiah Stane (Jeff Bridges) - who hadn't yet outed himself as a card-carrying villain - plays the piano in the presence of Tony Stark and Pepper.

You couldn't be blamed for thinking nothing of it, but for anyone acquainted with classical music, it was a dead giveaway as to Stane's true intentions.

Stane is actually playing Antonio Salieri's Larghetto from his Piano Concerto in C, and in pop-culture Salieri is commonly depicted as the rival of Wolfgang Amadeus Mozart and potentially even his killer, as was immortalised in the classic 1984 film Amadeus.

That Stane is playing Salieri on the piano is all too fitting considering that, allegedly like Salieri, he grew envious of a younger talent who surpassed him and consequently went on to plan their demise.

While historians generally consider the popular characterisation of Salieri to be false, the saboteur/murderer label has nevertheless stuck, and is clearly what Stane's choice of music is referencing.

And yet, it wasn't until Redditor Capt-Enterprise took note of the reference in 2017, over nine years after Iron Man's release, that this brilliantly sly flourish was picked up by the wider fanbase. Incredible.