History: The rarely seen back of the Hoover Dam before it filled with water 1936 [950 × 760]

http://i.imgur.com/EiuJ0nz.jpg via /r/HistoryPorn https://www.reddit.com/r/HistoryPorn/comments/4wwif8/the_rarely_seen_back_of_the_hoover_dam_before_it/?utm_source=ifttt