The cinematic experiences we refer to as action films come in many complex shapes and sizes.
Some high octane features focus on a badass lead character taking out goons and henchmen en route to completing their compelling mission. Other action adventures are presented in a more fantastical light, but still come equipped with mesmerising battles, showdowns and chases.
Yet, even though these following ten action spectaculars often differ in style and tone, they all still share one interesting feature. There's always more than what meets the eye, once you clear through the thick cloud of dust post-explosion.
As with any brilliant secret detail a director sneaks into their picture, each one of these action movie hidden treats adds more weight to a significant moment in the gripping film, suggests an intriguing larger universe or even subtly foreshadows the fate of the characters we're watching on screen.
In all honesty, though, no action fan is actually expected to catch each and every glorious piece of information offered up to them in every heart-stopping movie. So, if you were too busy being distracted by warring ships, high speed car chases or Dwayne 'The Rock' Johnson's biceps to catch these little details, don't worry; WhatCulture.com has you covered.
10. Kingsman: The Secret Service - Were The Beatles Secret Agents?
In Kingsman: The Secret Service, when 'Eggsy' (Taron Egerton) is finally introduced to the secret British spy organisation by Harry 'Galahad' Hart (Colin Firth), he's left stunned by the overload of new information.
This mixture of shock and excitement is captured perfectly when the young chav is seen gawping at the vast array of vehicles Kingsman have tucked away underground, with Galahad noting that he and Eggsy's father had the same look on their faces when they first laid eyes on the base.
Yet, while Eggsy and most of the audience were likely just drinking in the sheer amount of differing vehicles on show in the hanger, one specific mode of transport stuck out more than the rest.
To the right of the screen a vibrant yellow submarine can be seen. You know, like the one The Beatles bobbed around in back in the 60's?
Admittedly, this one looks a bit more realistic and practical than the animated sub seen back in the day, but it's still a bright yellow underwater craft with four portholes...one for each band member.
But the question is, was this submarine simply another nod to British culture (an iconic double decker bus is seen behind it, too) or were John, Paul, George and Ringo also secretly members of Kingsman?
Now, there's a movie we need to see.