
Colorado river’s Hoover Dam contains enough concrete to pave a standard highway from San Francisco to New York City, and the 90-year-old engineering marvel is still growing stronger | World News
Image Credit: By LICKO – en.wikipedia, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1427004 Standing in the brutal heat of the black canyon, Hoover Dam on the great Colorado river, was not just a construction










