Grand Coulee Dam, Columbia Basin Reclamation Project. The east face of block 31 with a portion of the deep crevice shown in the foreground showing the high trestle, elev. 1028, high pour in center of picture at elev. 915; bottom of crevice at elev. 795; and deck of low trestle at elev. 950. Sourced from the Library of Congress.
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