Deep underground in the foothill of the Alps in northern Italy is a magnificent temple so secret that even the Italian government didn't know of its existence until just recently:
... the 'Temples of Damanhur' are not the great legacy of some long-lost civilisation, they are the work of a 57-year-old former insurance broker from northern Italy who, inspired by a childhood vision, began digging into the rock. [...]
Volunteers, who flocked from around the world, worked in four-hour shifts for the next 16 years with no formal plans other than Falco's sketches and visions, funding their scheme by setting up small businesses to serve the local community.
By 1991, several of the nine chambers were almost complete with stunning murals, mosaics, statues, secret doors and stained glass windows. But time was running out on the secret.
The first time the police came it was over alleged tax evasion and still the temples lay undiscovered. But a year later the police swooped on the community demanding: "Show us these temples or we will dynamite the entire hillside."