The entrance of an exploratory tunnel dating from 1951 for the proposed Marble Canyon Dam in the Grand Canyon.

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The entrance of an exploratory tunnel dating from 1951 for the proposed Marble Canyon Dam in the Grand Canyon. The color of the rubble shows that only the surface of the canyon wall is red (from iron oxide).

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Size: 5129px × 3188px
Location: Grand Canyon National Park
Photo credit: © Andy Millard / Alamy / Afripics
License: Royalty Free
Model Released: No

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