You're lost and alone in a dark cavern.

Jake finds himself wandering through a dark cavern with high walls.

The beech woods, especially, can be like dark caverns.

Books were written, front pages were splashed, serious conferences convened, in which dark caverns and human sacrifice were earnestly discussed.

They are normally only encountered in deep, dark caverns, far beneath the earth.

Finally, in 1992, helped by photography from the space shuttle, they located the ruins in a collapsed limestone cavern almost underneath their base camp.

Excavating beneath an ancient fort, they found a limestone cavern into which the fort collapsed after an earthquake.

The limestone caverns were formed over time, as water seeped into and dissolved local bedrock, forming stalagmites, stalactites and flowstones.

Some of the limestone caverns are open to the public.

A 1.7 km/5577 ft length of twisting, turning limestone caverns have been outfitted with metal walkways, becoming quite narrow at some points, and subdued lighting.

For 25 years, the cooperative has mastered the art and science of compressing air, storing it in a salt cavern beneath the earth, and using it to produce electricity.

At night, while you sleep and your appliances rest, the plant uses excess electricity from the grid to compress air and pump it underground into an airtight salt cavern.

A salt cavern facility may occupy only one one-hundredth of the area taken up by a depleted gas reservoir facility.

The walls of a salt cavern are strong and impervious to gas over the lifespan of the storage facility.

There are three principal types -- depleted gas reservoirs, aquifer reservoirs and salt cavern reservoirs.

But ground penetrating radar had provided compelling evidence and the following spring he would defrost the specimen with hairdryers in a specially adapted underground cavern.

The stuffy underground cavern lacked windows, natural light and ventilation.

The process created an underground cavern whose roof rose higher as the salt was extracted.

Now a group of amateur treasure hunters claims to have located the loot in an underground cavern.

After checking in at one of 120 kiosks, passengers leave the underground cavern and enter a long, thin space through which they move on the way to their aircraft.