An ancient man-made near ground surface rock cavern group was found in Longyou County, Zhejiang Province. The 24 large caverns were excavated 2000 years ago.

浙江省西部龙游县的龙游大型古地下洞室群由24个洞室组成，该洞室群开挖于2000年前。

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The Longyou large ancient underground caverns contains the long-term integrity about two thousands years, but the field investigations show that the caverns are being up against many diseases.

龙游大型古地下洞室群虽然已保持了长达两千年之久的完整，但是现场调查发现，这些洞室存在着许多病害现象。

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In 1992, four local peasants found large-scale ancient man-made shallow rock caverns in Longyou, Zhejiang.

一个超浅埋大型古地下洞室群于1992年在浙江省龙游县被四个农民发现。

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Another possibility under study in various parts of the world, is compressing large volumes of air into caverns, salt domes or other subterranean features and retrieving energy from the released atmosphere as it escapes.

FORBES: Storage, Not Generation, is the Challenge to Renewable Energy

This involves compressing air and storing it in large repositories, such as underground salt caverns.

ECONOMIST: Energy storage