The question of whether or not there is life on the planet Mars has been answered definitively for generations now. But that doesn't stop the more imaginative among us from asking the question, "What if?" As in, "What if there were life on Mars?" Here are six movies about life on the red planet-either as visitors to Earth, or as parties to visitors from Earth.

"John Carter"

One of the first storytellers to hypothesize about life on Mars was Edgar Rice Burroughs, whose novels featuring Civil War era he-man John Carter getting transported to Mars and having all kinds of swashbuckling adventures were quite popular in their day. But it wasn't until 2012 that a movie version of Carter's adventures on "Barsoom" was made, and judging by its rather toxic box office performance, it's unlikely we'll see another any time soon. It's a shame, though, since the movie is so much fun.

"The War of the Worlds"

Another author who told tales of life from the planet Mars was HG Wells. Unlike the "John Carter" stories, his "The War of the Worlds" has been adapted to film plenty of times, but most agree that it's the 1953 version from sci-fi auteur George Pal that's the definitive movie version of the book. In it, Martians come to Earth bearing giant hovering ships and heat rays, but humanity defeats them with the power of love, or something. It was the 50s-what do you want?

"Mars Attacks"

A less reverent riff on alien invasion movies like "The War of the Worlds" is Tim Burton's "Mars Attacks", which divides its time between scenes of Martians wreaking havoc on humanity and humans being too dumb to handle the situation capably. It's hilarious, especially if you don't mind laughing during a movie featuring the violent death of thousands, if not millions, of people. And why would you mind that?

"Total Recall"

Martian life is one thing, but how about Earthlings living on Martian colonies? The red planet provides roughly half the setting for Paul Verhoeven's science fiction action classic "Total Recall". One possible downside of life on Mars is explored in the very first scene, as Arnold Schwarzenegger finds himself on Mars without a space helmet, causing his eyes to bug out of his head, which then explodes. It turns out to be just a bad dream, but it's not the kind you wake up from and forget about.

"Mission to Mars"

Brian De Palma is known for his psychological thrillers, but he also churned out a science-fiction ode to Stanley Kubrick's "2001" in "Mission to Mars", which has a group of astronauts traveling to Mars and discovering the secrets of the universe. Unlike the recent hit "Prometheus" (which features a similar premise, sans Mars), "Mission to Mars" was a notorious flop. Maybe it's because there's little graphic violence in the story, or maybe it's just because people don't like movies about Mars.

"Robinson Crusoe on Mars"

Here we have a Mars movie that shows both Earthlings on Mars and some native Martians. If you want life on Mars, this is the movie that gives you the most of what you want. It features a lone astronaut, who crash-landed on the red planet, struggling to survive. Then, he runs into some Martians. Excitement and/or monkey endangerment ensues.