The crater that smiles back at Mars.
Galle Crater, a ~215 km impact basin on the eastern rim of Argyre Planitia, is famous for one uncanny detail: from orbit, features on its floor line up into a smiley face. Two dark patches read as eyes and a curved arc of hills as a grin, earning it the nickname the 'Happy Face Crater'.
Claim your plot here →The 'face' is pure pareidolia — the human habit of seeing faces in random shapes. The 'eyes' and curved 'smile' are ordinary geological features: an arc of low hills and dark deposits on the crater floor that happen to align into a grin when viewed from above. Viking orbiters captured it in the 1970s and it has charmed people ever since.
Galle is named after Johann Gottfried Galle, the astronomer who first observed the planet Neptune. The crater also gained pop-culture fame after appearing in the comic Watchmen, cementing the smiley as one of the most recognizable natural formations on Mars.
At ~215 km across, this single crater is wider than many nations, from Wales to Belgium.
Like the 'Man in the Moon,' the smile is an illusion of light, shadow and terrain — not a designed feature.