https://www.news.com.au/national/nsw-act/subterranean-sydney-eerie-underground-world-right-beneath-the-cbd/news-story/de0147c78c833003c918aba0413fcfa8
>very last line
LOCKED away under the hustle and bustle of Sydney’s major train stations lies an extensive network of train platforms, tunnels and tracks that were completed in the 1920s but have never been operational.
During the construction of the City Circle and Central to North Sydney railways lines, additional tunnels and platforms were built in the CBD for proposed routes to Bondi and the Northern Beaches, to prevent disruption at a later date to existing services.
The labyrinth extends one kilometre in each of two directions from St James Station, about 30 metres below Hyde Park and past the Cahill Expressway entrance off Macquarie Street.
It was one of the first underground stations in Australia, completed in 1926, but the plan to continue works on additional lines was canned when the Great Depression hit.
The site has since led “a colourful life”, serving as a bomb shelter during WWII, a mushroom farm, film set, an Army training ground and a dark playground illegally accessed by secret societies who practice witchcraft and black magic.