NASA's Curiosity Mars rover looks back down at "Marker Band Valley" after climbing a steep slope. This mosaic, made of five images that were stitched together after being sent to Earth, was captured by the rover's Mastcam on June 21, 2023, the 3,865th Martian day, or sol, of the mission. The color has been adjusted to match lighting conditions as the human eye would see them on Earth. Curiosity struggled to climb a 23-degree slope that had slippery sand and wheel-size boulders. These three factors – the incline, the sand, and the large boulders – combined to make this Curiosity's toughest climb yet. https://photojournal.jpl.nasa.gov/catalog/PIA26011