Crystal Cave in Put-in-Bay, Ohio, is technically a misnomer. This “cave” is actually a “vug,” or a large cavity inside a single rock. In this case, this rock happens to be the largest known geode in the world.
Discovered in 1887 by workers digging a well for winery owner Gustav Heineman, the vug got its name from the three-foot-long Celestine crystals poking out from the walls. Though many of those crystals were mined for fireworks, Crystal Cave remains open for visitors to explore.
Those who take a tour of the cave can also expect a look inside the Heineman Winery.
– Jacqueline Gualtieri, The Ohio 100