The Libraries Hidden in Salt Mines

Far below the surface of Hutchinson, Kansas, lies a strange and sprawling underground world carved from ancient salt.

Known as Strataca, this working salt mine is more than a geological wonder—it’s a highly secure archive protecting some of America’s most irreplaceable treasures.

Tucked into this subterranean vault are thousands of original film reels, historic photographs, NASA footage, microfiche, and government documents.

It’s here that the original negatives of films like Gone with the Wind and The Wizard of Oz quietly rest, perfectly preserved in the dry, stable climate.

Why Store It in Salt?

The environment deep inside the salt mine is incredibly stable. With constant temperature, low humidity, and protection from natural disasters, it offers the perfect conditions for preserving fragile materials. Paper doesn’t decay, film doesn’t fade, and there’s no threat from fire, flood, or pests.

Security is another advantage. With hundreds of feet of solid rock overhead, the vault is naturally fortified and nearly impervious to outside threats.

A Public Peek Underground

Though much of Strataca remains restricted, part of the mine is open to the public as a museum. Visitors descend by elevator, explore historic salt mining tunnels, and ride a train through corridors lined with glittering salt crystals. It’s a rare chance to step into a space where geology meets memory—and to see firsthand how a mine became a modern-day vault.

But Strataca isn’t the only underground archive of its kind…

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