AMC's The Walking Dead first premiered in 2010. Since then, it has spanned over a decade with eleven tense seasons and the spinoff series Fear the Walking Dead. With recent news of even more spinoff series, fans are eager to see which characters and storylines might get featured.

When looking at The Walking Dead's expansive universe, which includes a wide array of characters, plots and locations, it's easy to get wrapped up in the intricacies of the post-apocalyptic zombie series. Revisiting the pilot episode of The Walking Dead, which aired on October 31, 2010, and is titled "Days Gone Bye," helps to bring back the original point of the show. Following classic zombie films like George A. Romero's 1968 film Night of the Living Dead, The Walking Dead found its strength in portraying Rick Grimes's (Andrew Lincoln) nightmarish foray into the world of the undead.

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The Walking Dead Pilot

"Days Gone Bye" plays with time to create an atmosphere of dread throughout the episode. The opening scene, where Rick encounters a zombie child and is forced to shoot her, exists outside the rest of the events of the pilot. While it's implied to take place after Rick leaves Morgan (Lennie James) and his son Duane (Adrian Kali Turner) in search of the refugee camp in Atlanta, using this scene before viewers even know Rick's name sets up the unknown horrors that have taken over the world. The first zombie (or "walker") that Rick and audiences see is a young girl. Children often symbolize innocence, but in the world of The Walking Dead no one is safe from the living dead. This scene immediately establishes a dark tone and sets a precedent for the violence to come the survivors' way.

Later on in the episode, Rick recovers from a gunshot wound in a hospital. He is visited by his partner, Shane (Jon Bernthal), who brings him flowers and talks to him. However, time is distorted, and Rick wakes up weeks after an unknown, but lengthy, period of time passes. The flowers are now dead and wilted. Warping time in this manner keeps the audience as confused as Rick, but with the knowledge of the horrors of the opening scene. Viewers and Rick are unsure what happened to his family, the hospital staff or anyone else. Rick's eerie trip through the hospital gives clues as to the level of destruction that he was unconscious for. Seeing the blocked-off wings filled with the undead, and parking lots filled with corpses hints at an apocalypse that no one was prepared for. At this point in time Rick doesn't even know if anyone else is still alive out there, and neither do viewers.

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Rick Grimes in The Walking Dead Season 1 premiere.

The Walking Dead's first episode doesn't hold back on shocking images of the walkers. After Rick leaves the hospital he travels back to his home and encounters a gruesome walker. This walker, missing the bottom half of its body, is determined to get to Rick. He is unaware of what exactly went down during his time in the hospital and feels remorse for the zombie, who he still views as human. Aside from establishing some "rules" about the undead, this interaction outlines Rick's morals. His remorse also shows that death is not always the worse thing that can happen to someone.

The idea of humanity persevering against all odds is perhaps the core theme of The Walking Dead. The survivors must reconcile their differences to stay alive, but this is difficult when the entire world has fallen apart. "Days Gone Bye" reveals the magnitude of destruction, with entire cities collapsing and whole populations turned into the walking undead. While Rick is still hopeful, he's surrounded by evidence of complete destruction. From the iconic "Don't open dead inside" message spray-painted in the hospital, to Morgan's dead wife, to people committing suicide out of sheer hopelessness, Rick is presented with the question: What would you do to survive? Like the classic horror film Night of the Living Dead, "Days Gone Bye" uses fear, uncertainty and rapid changes to the concepts of "death" to establish a new world where no one is safe.

The Walking Dead is now one of the largest television series of the 21st Century. While the show's universe has expanded and Rick and the others try to survive a now-hostile world, the pilot episode establishes many of the show's core themes that later episodes call back to. "Days Gone Bye" introduces Rick, and viewers, to a world filled with horrors that fans can only hope never enter reality and remains crucial for understanding the show's core message.