Industry
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What was once the ocean floor provided silica sand for glass making during the early twentieth century. When R. Marvin Greenhouse began hollowing these hills to mine the silica sandstone, the cavernous rooms left behind would go on to fascinate people for decades. Today the portal opens into vast underground spaces with a distinctive human and geologic history and serves as the entrance to a unique underground visitor center.
Hear stories like this as you drive
ExploreHere reads historical markers out loud as you pass them: over 325,000 stories across the US. No account needed.
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California · United States
