With such a vast and detailed comic book history, it’s hardly surprising that Marvel stuffs their films with as many callbacks and Easter eggs as possible. The Marvel Cinematic Universe is definitely accessible to those without a shred of comic knowledge, but the films also reward observant viewers who have more than a passing knowledge of Marvel lore. As one of Marvel’s oldest and most popular heroes, Captain America has more opportunity than most characters for obscure references and delightful visual callbacks. With three films dedicated to Cap’s adventures in the MCU released so far, it’s a good time to look back at each film in the series — The First Avenger, The Winter Soldier, and Civil War — and the various hidden details they contain. Only the most dedicated Cap fan would have noticed all of the following Easter eggs.