Galle is often known as the "happy face crater" because the illusion of a smiley is created by a curved mountain range in the southern part of the crater and two smaller mountain clusters further north. The formation was first photographed by Viking Orbiter 1.
As the smiley is a key motif in the comic bookWatchmen by Alan Moore and Dave Gibbons, the crater was used as a story location after the coincidence was noted by Gibbons. According to Gibbons, the similarity "was almost too good to be true. I worried that if we put it in, people would never believe it." The actual crater was visualized in the 2009 film adaptation of Watchmen.
A second "happy face crater", smaller than Galle and located at 45.1°S, 55.0°W in Nereidum Montes, was discovered by the Mars Reconnaissance Orbiter on January 28, 2008.