A compilation of salt pond shots. Most were taken inbound to SFO, on the former wetland shores of San Francisco Bay. Sea salt is produced by evaporation of still impounded sea water — a process that takes several years. At first the ponds turn green with algae, then red with brine shrimp (the same tiny animals that produce "red tide" in the ocean). They then turn pink, brown or orange as the water finishes evaporating, leaving a thick layer of white salt, which is harvested by special equipment. The ponds are owned and operated by Cargill, which has owned them since 1978. While the ponds were once rationalized as an agricultural innovation and an economic boon, they are now consideredbad for the environment, because they eliminate much of it. San Francisco Bay is among the few wetlands on the otherwise steep and rocky West Coast of the U.S. Here's Cargill's page on the ponds, offering their side of the story, along with helpful stuff about the ponds themselves.