Created in limestone by the slow corrosion of slightly acidic rainwater over millions of years, the cave is split into two parts, "Lower Long Churn" and "Upper Long Churn", each active with a stream, and is connected to the nearby Alum Pot and Diccan Pot.

[2] Lower Long Churn leads to an exit into Diccan Pot, followed by the "Cheesepress", a narrow squeeze which is notorious for its tightness but which can be bypassed.

The end of the Lower Long Churn is a chamber which opens on a window into Alum Pot, which is much more technically difficult to descend (or ascend).

[1] Outdoor author Alfred Wainwright wrote of the system: It is quite possible and in fact easy to die a horrible death by straying off route.

In 2007, a man and woman both drowned in the same incident,[6] and in 2008 two separate groups were trapped in the cave during storms, although there were no deaths.