Throughout history, our planetary next-door neighbor Mars has captured our imagination--from little green men to "man-made" canals and satellite photos revealing a giant "face". As one of the most likely spots in our solar system where some form of life may exist or have existed, we have spent billions on missions designed to disclose the red planet's tightly-held secrets. We'll trace man's journey of discovery of this fascinating planet, and focus on NASA's great successes and heartbreaking failures.