This image was taken by NASA's Mars Exploration Rover Spirit's front hazard avoidance camera during Spirit's 154th martian day, or sol, on June 9, 2004. The "Columbia Hills" appear against the horizon. Directly in front of the rover is the highest of the hills, "Husband Hill," approximately 90 meters (295 feet) tall. The rock in the foreground is larger than other surrounding rocks, approximately 35 centimeters (14 inches) across, but was not an observation target for Spirit. The tread marks in front of the rock are not a trench, but simply evidence that the rover passed by as it continued its journey toward the Columbia Hills.