How We Have Explored Mars: Top 12 Events (PHOTOS)

Tomorrow, NASA's latest mars probe, the Mars Science Laboratory rover "Curiosity," will land on the Red Planet. It is the largest, heaviest and most ambitious rover ever to head off to Mars. If successful, Curiosity is likely to change much about the way we look at Mars. Long-term geological processes, especially those involving the copious amounts of water now known to exist as ice all over Mars, will be examined. Weather patterns and the likelihood of microbial life (or at least organic compounds) will also be explored.

But what has brought us to this watershed moment? How did Mars evolve from a red smudge in the lenses of giant telescopes to a planet we know better than any save Earth?

Let's take a look back at our discoveries about Mars and the many missions of NASA and others that have brought us to this amazing time in history.

Rod Pyle is the author of Destination Mars: New Explorations of the Red Planet (Prometheus Books, 2012).

Pivotal Moments in Mars History