[5] [1] The caves are thought to have been formed around 500,000 years ago,[5] although the process by which they were created began during a much earlier period in which the region was covered by ocean.

[6] They were discovered in January 1860 by William and Mark Newbould,[7] who were amongst a group of miners prospecting for lead veins in the Yorkshire Dales.

[11] Long claimed that he had also discovered an underground lake, but is said to have sealed its entrance when the caves' owners refused to allow him a share of the revenue generated by tourism to the site.

[4][failed verification] Stump Cross developed into a tourist destination in the decades that followed, gaining an information centre, gift shop and a two-bedroomed cottage for the owners.

[5] In 1963 Geoffrey Workman spent 105 days in the caves, a world record, as part of a study on the effects of isolation on the body.

[5] Ownership of the site passed to the Bowerman family, who also part-own the Richmond Brewery Company, which in 2008 released an ale named after Stump Cross.