In this area, in 1952, two young English potholers discovered that a river disappeared somewhere under the ground. They decided to follow suit. Water has to go somewhere, right?
That turned into a real discovery. They crawled through a 500 meter long tunnel, just large enough to crawl through, while the river flowed past them. Had a thick stone blocked their way, they would have to crawl backwards out again, because nowhere was a place to turn.
With almost no fuel for their lamps left, they decided to extinguish the light, so later they could see where they came. In that narrow, pitch-black world the change of sound was the only thing that indicated that they had arrived in a large space, numb and with bruised knees. When they lit their lamps, they were beaten with wonder when they saw the Great Stalactite, the only stalactite in the entire room. They did not dare to talk aloud, worried that the vibration of the first voices ever to sound in this hall since the beginning of Time should cause the giant stalactite to shatter.
Varley and Dickenson had discovered the largest stalactite in the world.
Fortunately, as a tourist you don’t have to crawl as a mole through a 500 meter long, narrow tunnel. Doolin Cave has been provided with a concrete shaft where a staircase leads the visitor 80 meter down. From the bottom of the shaft, the final piece of the route the explorers followed has been carved out. You can still see that the original corridor was incredibly narrow.
To achieve a dramatic effect, the visitor is led into the darkness of the dome to revive the experience of the explorers. Then – [drum roll] – the light goes on and you see the world’s largest free-hanging stalactite. Seven meters high and weighing 10 tons. The colossus is hanging there now for some one million years, like the sword of Damocles, over the stream that led to the discovery.
The origin of the cave goes back about 360 million years, when Ireland was part of a shallow tropical ocean at the equator. Dead animals, plants and coral left a thick layer of limestone on the ocean floor. This layer was not uniform, there were terraces and cliffs. During successive ice ages (the last one ended 15,000 years ago) the limestone layer was worn down by the ice. Thus it seems that in some places the bottom is paved with large, flat limestone slabs (pavement). The soil is full of holes, cavities and passages, carved out by the water, far below the surface. Limestone (calcium carbonate, CaCO3) is in fact soluble in water that contains carbon dioxide (CO2). In the course of time, dripping calcareous water forms (hanging) stalactites and (standing) stalagmites in the caves.
The result of the action of ice and water on the limestone is the characteristic karst landscape of The Burren.