Two panoramic images taken by Mars Rover Opportunity on July 10, 2015 show what appears to be a dome.
The isolated spherical structure sits on top of a hill and it looks quite different than the surrounding rocks and soil.
A glow or light in the middle of the dome suggests it may be metallic and reflecting sunlight. Or it could be a window emitting internal light. To the right of the dome you can see a smaller construction.
If this dome is not natural and it is indeed a building-like structure, could it be an outpost, a storage facility or a living quarter?
We may wonder who made it!