The All-American Canal, the largest irrigation canal in the world and a key landmark along the U.S.-Mexico border, is the focus of this image, taken by the crew of Expedition 18 aboard the International Space Station. The prominent dark line crossing the image is the canal, which is crossed in this view by Interstate Highway 8. The canal carries 26,155 cubic feet of water per second westward from the Colorado River to support the intensive agriculture of California's Imperial Valley to the northwest and nine cities, including San Diego. The canal system is the Imperial Valley's only source of water, and it allows irrigation of more than 500,000 acres of agricultural fields. The Coachella Canal, one of four main branch canals, leads water north to Imperial Valley.
Image Credit: NASA