http://www.theguardian.com/world/2014/jun/19/injured-explorer-rescued-germany-deepest-cave
That cave is 19km long. He was 6.5km in.
@Oliver Schick started
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http://www.theguardian.com/world/2014/jun/19/injured-explorer-rescued-germany-deepest-cave
That cave is 19km long. He was 6.5km in.