King Jan III Sobieski of Poland began construction on Wilanów Palace in Warsaw, complete with a vast network of underground ...

A remarkable underground city, believed to have been built for security as well as water access, has been discovered beneath ...

A long-rumored network of secret tunnels sketched by Leonardo da Vinci has been uncovered beneath the Sforza Castle in Milan, ...

Rail engineers working on upgrades to a railway station in Wiltshire discovered a series of mysterious tunnels exposing the station's hidden history ...

Researchers have discovered hidden tunnels beneath Milan’s Sforza Castle, which may have been used for military defense, ...

Crane, R-Ariz., and Rep. Lou Correa, D-Calif., introduced the Subterranean Border Defense Act to require an annual report on the federal government's knowledge of illegal underground border-crossing ...

In addition to the tunnel, medium-size underground rooms were also detected at a second subterranean level, she added. Researchers suspect that there are more subsurface structures to be uncovered ...

Deep beneath the Dutch city lie vast subterranean spaces that have served as art canvases, air raid shelters and a strategic ...

While NYC’s cow tunnels are perhaps the most famous, they were not unique to the metropolis. Around the world, farmers and ...