Mars is one of only five planets that can be seen from Earth without a telescope. The other planets are Mercury, Venus, Jupiter, and Saturn. Throughout history, people have been fascinated by Mars. Many theories have developed based on early observations of the Red Planet. Space probes continue to this day to explore the mysteries of Mars.
1659 - Dutch scientist Christian Huygens sketches the first map of Mars. It includes a dark spot, later known as Syrtis Major, and the polar caps.
