Mars is the ruby jewel in our night sky and arguably the hottest travel destination in the Solar System. Thanks to a robot invasion from Earth that began in the 1960's, we probably know more about Mars than every other destination in the Solar System combined. Not bad for a planet so cool that the average summer temperature makes a winter in Antarctica seem positively balmy. It might be freezing, there might be nothing for a human to breathe, but of all planets we know this rocky, red one is the most similar to home. Pack a good spacesuit and plenty of oxygen and prepare to be amazed. Here, under butterscotch skies, are vast rust-colored deserts and titanic canyons, towering volcanoes three times as high as Everest and mile-deep polar caps made of two different kinds of ice. This journey itself is a space traveler's dream: a short hop to the planet next door and a wealth of things to see and do. Here, on the fourth rock from the Sun, is our best chance to step into the rest of the Universe and the most likely place we know to encounter the alien life forms we might share it with.
—Richard Smith