The Galle Crater, also known as The Happy Face Crater, is an odd geographical wonder on the face of the planet Mars. The Galle Crater is located on the east side of the Argyre Planitia at the coordinates 51.1 S, 31.3 W.
The Galle Crater was first photographed in the synoptic observations during the Viking Orbiter 1 mission to Mars in 1976. However, it wasn't paid much attention at first due to the mysteriousness of the supposed "face" that was on Cydonia. After the "face" was proven to be a trick of the light, eyes turned back to the Galle Crater. The Galle Crater's similarity to a smiley face was shown to be completly real. All of the peaks and ridges are the effects of a single meteor crashing into Mars and the natural effects of the planet.
The Galle Crater stretches for 215 kilometers(134 miles), and constantly has a wintertime frost on the the crater's south slopes.
For a nice view of the crater you can look at:
Or any of the other links listed as sources.