National Geographic: A millennium agojust yesterday, in geologic timeNative Americans waited all winter for rains that never came. They waited the next winter and the next. Then the marshes of their sacred San Francisco Bay turned from cattails to salt grass. Fishing declined and the Native Americans could no longer rely on the bounty of the bay. Finally, they left, hungry and thirsty, in search of water. Now, as modern Californians hope for fierce storms to break a dangerous dry spell, the questions arise: Is the...