Even now, after the Mars Rover has explored a tiny fraction of the planet, there's still so much we don't know about our celestial neighbor. If popular culture keeps harping on the same theme, about the sheer inhospitableness and frightening landscapes of Mars, it's because there's still the chance that there's something lurking there, under the red sands, waiting to strike.
Now, there's a personal account to add fuel to the fire. A US ex-Marine, only known as Captain K, surfaced in 2014 with the astounding claims that he had been part of a government-sanctioned "Mars Defense Force", living 17 years on the planet and fending off Martian threats. Consisting of American, Russian, and Chinese troops, this MDF was part of the greatest cover-up the world has ever known.