[Editor’s Note: This list was originally published in May 2016 and has since been updated.]

So…what is sci-fi? It’s not the easiest question to answer when “sci-fi elements” permeate so many of the biggest blockbusters: thought-provoking genre concepts flattened into one-size-fits-all franchise fodder that make countless titles “feel” and, on occasion, even look the same.

Yes, science fiction is rooted in profound origins, examining humanity’s deep-seated fear of itself and the intimidating possibility of worlds unknown. But the last two decades have seen a metaphoric rush on sci-fi storytelling that’s left the once niche subgenre a supersaturated movie market. On the one hand, that’s produced an onslaught of sci-fi(ish) titles that aren’t always up to snuff. But on the other, it’s prompted some of the best sci-fi films ever made. Masterworks like “Everything Everywhere All at Once” and “Nope” both arrived in the past two years, and top our list at number five and number eight respectively.