Exploring unknown caverns and navigating underground rivers is what makes caving so thrilling.

探索未知洞穴，航行于地下暗河使得洞穴探险分外刺激。

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The main watercourse of Yangtze was made of some surface river sectors and underground rivers.

地表河与地下河相连接构成长江主河道。

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Erosion by the Yangtze river had formed numerous gorges and construction was dogged by underground rivers and caves.

沿路因长江侵蚀有许多峡谷，而且建设经常被暗河和山洞所阻断。

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Discover the area's wildlife, lagoons and underground rivers at Xcaret Park.

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They are widely regarded as a world-class natural attraction containing marvellous stream passages formed by three rivers that sink underground on the slopes of Cuilcagh Mountain.

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This is the water found in lakes, rivers, reservoirs and those underground sources that are shallow enough to be tapped at an affordable cost.

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