For nearly eighty years, alien invasion films have had a long, rich, and at times cheesy presence in cinema. Before modern day movies like Nope changed the course of alien invasion movies. Films like The Purple Monster Strikes, The Day the Earth Stood Still and The War of the Worlds, were alien invasion stories that peaked audiences and elicited responses from generations. What is it about this subject that caused such an influx of movies in the '40s and '50s? That answer can be boiled down into a couple different points, and they both are direct reflections of where both the United States and the world overall stood throughout those two decades. Let's take a trip down memory lane and analyze just what made this genre of film so huge in the '40s and '50s.

The World Enters the Nuclear Age

Godzilla King of Monsters
Embassy Pictures 

The 1940s brought with it extreme lows and extreme highs the world over. Hitler and the Nazis were defeated in 1945 and their Japanese allies soon thereafter. It was the defeat of the Japanese at the hands of the Atomic Bomb that plunged the world into the nuclear age. The events at Nagasaki and Hiroshima in August 1945 brought to life a concept only dreamed about in fiction. This new reality was ripe for filmmakers in the science fiction genre. They may not have been the scariest movie aliens, but the monsters in these films now carried a weight with them that in this new nuclear age and a belief that a creature like Godzilla or The Beast from 20,000 Fathoms could actually exist. This terrifying concept then peaks the interest of a moviegoer that may not have otherwise been down to see these types of movies in the '40s and '50s. Other movies such as Creature from the Black Lagoon and The Mole People, while not specifically creatures born from a nuclear event, still carry with them the gravitas of an unknown creature lurking in the shadows of this new world.

Cold War Paranoia/Invasion of the AdversaryIt Came From Outer Space

Along with the nuclear age, the late 40s brought with it a Cold War that would last for the next forty-four years as the United States and Russia would wage geopolitical war against one another without a single shot being fired. The nuclear age was alive and well in the late '40s and '50s as a newly nuclear Russia and the United States would live in fear of one another for the following four decades. The fear of Russia, commonly known as The Red Scare, would cause paranoia to run rampant in the U.S., with schools even holding air raid drills teaching children to duck-and-cover under their desks in case of an atomic bomb attack by Russia, a surefire tactic to save them from a nuclear blast... There was growing tension as the two global powers engaged in this new world arms race. The real life fears were perfect tools for filmmakers in the '40s and '50s; the fear of an invasion of the adversary was as real as it would ever be up to that point.

To moviegoers in the '50s, an invasion by space aliens like in Invaders from Mars, It Came from Outer Space, or the anti-communist The Day the Earth Stood Still, were as real of a possibility as an invasion by the Russians. People tend to be drawn to their fears as a way of trying to rationalize them, leading to the boom in the alien invasion films during this time period.

Related: Best Alien Invasion Movies, Ranked

Fear of the "Other"

Invasion of the Body Snatchers
Allied Artists Pictures

Other films take a more personal approach to the invasion angle. The one thing that alien invasion films do best is play off of people's fear of the "other", a person or group of people invading their world, their way of life. Films like Invasion of the Body Snatchers feature a plot where a man's community is being replaced with emotionless alien duplicates, eventually creating distrust of one's neighbor, becoming the perfect allegory of its time. With talks of Russian spies infiltrating the United States in the '50s during the Cold War, it would not have been uncommon for this fear and mistrust of your neighbor from science fiction films to manifest itself in the real everyday lives of people. Parallels can also be drawn to demographic changes that began to occur in America in the 50s. Things were changing, neighborhoods were developing, other cultures were blending, and not everyone was positively receptive to those changes.

Movies are always intricately tied to the eras in which they were created. They are reflections of society into fictional storytelling. The two decades between 1940 and 1959 and the alien invasion films that graced the silver screen are perfect examples of this. We were at the time, and still are to this day, curious and interested in the unknown aspects of our universe. We also as a society have not come very far in progressing past our fears of nuclear war, or people that do not look like we do, of being "invaded". A sad truth reflected then and reflected now. Maybe in the event of an alien invasion, someone will be strong enough to lead the human race. Maybe Arnold Schwarzenegger?