Wapama Falls, Hetch Hetchy Valley, circa 1920. One
of San Francisco's lesser-known assets is its fabulous
water system, in use since 1934, which brings water underground
all the way from the high Sierra to a pristine reservoir
just south of the City called Crystal Springs.
The Sawyer Camp Trail, a popular route among cyclists,
joggers and hikers, runs along the Trail's northern end.
