The intricate lines angling and criss-crossing over the landscape are roads in extreme southwestern Kazakhstan. The turquoise areas on the left of this false-color satellite image are salt flats and marshes, some parts of which are submerged (dark blue). The body of water is Sor Kaydak, which was once a gulf of the Caspian Sea. As water levels have dropped, curious patterns in the landscape have emerged that reveal old tributaries. Image courtesy of USGS.