Not a real one obviously, but a dusty outline that may have been caused by a volcano.
The feature has so intrigued researchers at the University of Arizona's HiRISE telescope that they are planning to take a closer look to work out how big it is.
It's almost heart-shaped.
The University said: "The feature indeed does look like a heart. It is located south of Ascraeus Mons, which is a large volcano within the Tharsis volcanic plateau, so it is extremely likely that this feature was formed by a volcanic process.
"The feature rises above the surrounding terrain and we can see concentric ridges on its top.
"Perhaps this feature is an ancient vent structure (an opening in the ground from which volcanic lava emerges) that has been more resistant to erosion than the surrounding area, so that it resembles “inverted” terrains."
Researchers will take more images of the feature to in order to create a digital terrain model which will help with assessing it's height.