This image was taken by Mast Camera (Mastcam) onboard NASA's Mars rover Curiosity on Sol 3466 (2022-05-07 07:58:16 UTC).
Clearly not a natural formation.
"Just Another Non-Existent Terminal"
Janet, sometimes called Janet Airlines, is the unofficial name given to a highly classified fleet of passenger aircraft operated for the United States Department of the Air Force as an employee shuttle to transport military and contractor employees to Special Access Facilities (SAPF.) Its purpose is to pick up employees at their home airports and take them to their places of work. Then, in the afternoon, they take the employees back to their home airports. The airline mainly serves the Nevada National Security Site (most notably Area 51 and the Tonopah Test Range) from a private terminal at Las Vegas's Harry Reid International Airport.