Editing Tunnel (section)

== Secret tunnels ==
{{main|Secret passage|Smuggling tunnel}}
[[File:Underground Railroad Tunnel Door.jpg|thumb|upright|Door to a compartment where runaway slaves would sleep, on the [[Underground Railroad]]]]
[[secret passage|Secret tunnels]] have given entrance to or escape from an area, such as the [[Cu Chi Tunnels]] or the [[Gaza Strip smuggling tunnels|smuggling tunnels in the Gaza Strip]] which connect it to [[Egypt]]. Although the [[Underground Railroad]] network used to transport escaped slaves was "underground" mostly in the sense of secrecy, hidden tunnels were occasionally used. Secret tunnels were also used during the [[Cold War]], under the [[Berlin Wall]] and elsewhere, to smuggle refugees, and for [[espionage]].

[[Smuggler]]s use secret tunnels to transport or store [[contraband]], such as [[illegal drugs]] and [[weapon]]s. Elaborately engineered {{convert|1000|ft|m|adj=on|order=flip}} tunnels built to smuggle drugs across the Mexico-US border were estimated to require up to 9 months to complete, and an expenditure of up to $1 million.<ref name=Audi>{{cite news|last1=Audi|first1=Tamara|title=Drug Tunnels Have Feds Digging for Answers|url=https://online.wsj.com/news/articles/SB10001424127887323854904578264382749570570|access-date=4 October 2014|work=The Wall Street Journal|date=31 January 2013}}</ref> Some of these tunnels were equipped with lighting, ventilation, telephones, drainage pumps, hydraulic elevators, and in at least one instance, an electrified rail transport system.<ref name="Audi" /> Secret tunnels have also been used by thieves to break into bank vaults and retail stores after hours.<ref name=Colchester>{{cite news|last1=Colchester|first1=Max|title=Thieves Drill Into Paris Bank Vault|url=https://online.wsj.com/articles/SB10001424052702304739104575153530631794248|access-date=4 October 2014|work=The Wall Street Journal|date=31 March 2010}}</ref><ref name=Evans>{{cite news|last1=Evans|first1=Peter|title=Where 'Criminal Underworld' Is More Than a Euphemism|url=https://online.wsj.com/articles/where-criminal-underworld-is-more-than-a-euphemism-1412383000|access-date=4 October 2014|work=The Wall Street Journal|date=3 October 2014}}</ref> Several tunnels have been discovered by the [[Border Security Forces]] across the [[Line of Control]] along the [[India-Pakistan border]], mainly to allow terrorists access to the Indian territory of [[Jammu and Kashmir (union territory)|Jammu and Kashmir]].<ref name="arniatunnel">{{cite news|last1=Khajuria|first1=Ravi Krishnan|title=Day after India-Pakistan flag meet, BSF detects trans-border tunnel in Jammu's Arnia sub-sector|url=http://www.hindustantimes.com/india-news/under-construction-tunnel-being-dug-from-pakistan-side-unearthed-by-bsf-in-jammu/story-B1qgulsJCMQ8FOxWs3LYyO.html|access-date=10 December 2017 |work=[[Hindustan Times]]|publisher=1 October 2017}}</ref><ref name="sambhatunnel">{{cite news|last1=Iqbal|first1=Sheikh Zaffar|title=20-Foot Tunnel From Pakistan Found By BSF At Sambha, Jammu and Kashmir|url=https://www.ndtv.com/india-news/20-foot-tunnel-from-pakistan-found-by-bsf-at-sambha-jammu-and-kashmir-1659393|access-date=10 December 2017|work=[[NDTV]]|date=14 February 2017}}</ref>

The actual usage of [[erdstall]] tunnels is unknown but theories connect it to a rebirth ritual.