Asubterranean waterfall, tierous waterfall, or underground waterfall is a waterfall located underground, usually in a caveormine.[1] They are a common feature in cave systems where there are vertical or near vertical geological structures for the weathering process to exploit, and sufficient gradient between the sink and the rising.[2][3] Notable examples include Ruby Falls, 44 metres (144 ft) high, in Lookout Mountain Caverns, a show caveinTennessee[4] and Gaping Gill in the Yorkshire Dales, UK with a fall of 98 metres (322 ft). The highest known subterranean waterfall is in Vrtoglavica CaveinSlovenia, and is at least 400 metres (1,300 ft).[5]
