Long before Mars lander Curiosity was even a glimmer in an engineer’s eye, Carl Sagan was talking about exploring Mars. In 1977, he gave a series of six lectures for kids about exploring our solar system. Here they are, in order. Each is about 60 minutes long. You can also sign up for free and watch them all at The Royal Institution online.
#1 The Earth as a Planet
#2 The Outer Solar System and Life
#3 The History of Mars
#4 Mars Before Viking
#5 Mars After Viking
#6 Planetary Systems Beyond the Sun (this one you have to watch on YouTube)