The images that recently have gone viral actually date back to 2001.

Today, the planet Mars presents itself as a cold, arid desert, but its soil retains the imprint of a far more welcoming past.

Astronauts train to scale a Mars volcano at an analogue site in France. Lava tubes that crisscross the Martian surface might provide sanctuaries for the first human explorers on the Red Planet. (Photo ...