California HSR Palmdale - Burbank Alternatives - source: California HSR Environmental documents: https://hsr.ca.gov/wp-content/uploads/2022/08/PB_0_Summary_Rev11_Clean_A11Y.pdf

Adur-Worthing Council press release on tunnel proposal 6 Sept 2022

SCG Terratec S48C Samui Island breakthrough Owner of photo Terratec media information

Nordhavn tunnel map. from Vejdirektoratet (Danmark) report

source of this graphics: https://kommunikasjon.ntb.no/pressemelding/tilbydergruppen-nordland-forbinde-trekker-seg-fra-ops-prosjektet-e10-halogalandsvegen?publisherId=17847490&releaseId=17940014&lang=no

Mitma Granada Tunnel Renovations (graphics from Mitma release)

Implenia Brenner Northernmost tunnel from Implenia media release.

Ambito geográfico: Comunidad Valenciana via El Ministerio de Transportes, Movilidad y Agenda Urbana (Mitma)  

Posiva's spent nuclear fuel disposal. source: Posiva.

Acciona Helsinki seawater heat recovery tunnels (image Acciona press release: https://www.acciona.com/updates/news/acciona-enters-finland-worlds-third-longest-undersea-tunnel/?_adin=11551547647)