This image taken by the Mars Exploration Rover Opportunity shows the two holes that allowed scientists to peer into Meridiani Planum's wet past. The rover drilled the holes into rocks in the region dubbed "El Capitan" with its rock abrasion tool. By analyzing the freshly exposed rock with the rover's suite of scientific instruments, scientists gathered evidence that this part of Mars may have once been drenched in water. The lower hole, located on a target called "McKittrick," was made on the 30th martian day, or sol, of Opportunity's journey. The upper hole, located on a target called "Guadalupe" was made on the 34th sol of the rover's mission. This image was taken on the 35th martian day, or sol, by the rover's hazard-avoidance camera. The rock abrasion tool and scientific instruments are located on the rover's robotic arm.