Was Mars Ever Habitable?

NASA has followed the water on Mars, and has now progressed further to asking: is or was this environment ever actually habitable by life as we know it?  All such life has some common physical and chemical requirements, which we can look for via orbital remote sensing and missions to the Martian surface.  Recent results from the Curiosity rover are providing a delightfully nuanced answer to this question.  The talk will discuss how we arrived at Gale crater (versus the many other interesting places on Mars), what we have been doing there, and what we must do beyond Curiosity to answer our most fundamental questions about how the Martian environment has evolved over time.