Since telescopes glimpsed the surface of the Red Planet in the 1800s, Mars has been a source of endless fascination-for its potential habitability and the possibility that traces of ancient life forms reside in its polar ice caps, valleys, and volcanoes. See the desert world through the eyes of NASA's rovers, probes, and orbiters, from the first flyby in 1965 to the present-day Perseverance rover.