Curiosity rover was supposed to explore Gale Crater on Mars, while also photographing everything around it. It also photographed a "pyramid" on the surface of Mars.

What was labeled as a pyramid may actually be a large block and not a structure, but the clearly polished edges suggest otherwise. Add on to this the rover batteries that only function in Earth-like conditions and an Earth-like rainbow in the waterless Martian sky, and one wonders which planet the rover is actually on.