Proposed underwater tube crossing of Union Bay, Seattle, Washington, USA, 1960s for the (never-built) <a href="https://en.wikipedia.org/wiki/R.H._Thomson_Freeway" class="extiw" title="w:R.H. Thomson Freeway">R.H. Thomson Freeway</a>.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/24256351@N04">Seattle Municipal Archives</a> from Seattle, WA
CC BY 2.0
<bdi><a href="https://en.wikipedia.org/wiki/en:Seattle_Municipal_Archives" class="extiw" title="w:en:Seattle Municipal Archives"><span title="municipal archives of the city of Seattle">Seattle Municipal Archives</span></a>
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