The towering peaks of the Sierra Madre of Mexico dominate this image acquired by Aqua on February 15, 2006. The “Occidental” or western portion of this fabled mountain range appears as a dark brownish band running along the left side of the image, bracketed by the lush, green oasis of the Pacific coast to the left and the much lower elevation “altiplano” or high plain to the right. The top of the “Oriental” or eastern portion of the range is also visible on the right side of the image; the two branches converge further south, beyond the margin of this particular image. These features are joined to their counterparts on the U.S. side of the border: the Sierra Nevada, Great Basin, and Rocky Mountains, respectively. The forces that created this highly varied topography are still at work today, creating a large volume of volcanic and seismic activity in the area. This is due to the fact that Mexico sits atop several tectonic plates; some are spreading apart while others are being pushed together, producing stress – of several varieties. The region is also a hotspot of biological diversity, home to thousands of endemic plants as well as critical winter habitat for monarch butterflies.