The Mars rover Opportunity has taken the first close-up pictures ever of Martian bedrock, and these reveal important new details of the intriguing strata. The rover’s earlier observations revealed layering, as well as round grains in the soil, both highly suggestive of sedimentary rocks deposited in water. The new close-up images show that the thinness of the parallel layers of the rock continues down to the smallest scales the images are capable of showing. Furthermore, the small bead-like spheres seen earlier on the soil turn out to be heavily concentrated in the bedrock itself.