Police in Chihuahua, Mexico, say they are investigating social media claims of a possible second illegal tunnel between El ...

There are 570 highway tunnels in the United States just for large roads. Nehemiah Mabry, an engineer and CEO of Stem Media ...

Built on a limestone foundation, Valletta housed defense systems in deep tunnels during WWII that saved Malta and Allied ...

Complicating the Gateway project are the unknowns underground, from an 1800s-era bulkhead supporting Manhattan to a former landfill on the path.

In a twist worthy of a Renaissance mystery, Leonardo da Vinci's sketches have revealed hidden secrets beneath the Sforza ...