Water on Mars
The Mars flybys such as Viking, Mars Odyssey, Mars Global Surveyor, Mars Express, and the Mars Reconnaissance Orbiter had cameras.  They took pictures of what seem to be ancient lakes, ancient river valleys, and widespread glaciation. An orbiting Gamma Ray Spectrometer found ice just under the surface of much of the planet. Also, radar studies found ice that were thought to be glaciers. The Phoenix lander showed ice on Mars when it was landing. Phoenix also showed ice melting, snow falling, and even saw drops of liquid water.