There are 2,000 of these ancient tunnels throughout Central Europe, especially in Bavaria. No one is sure who made them or ...

Scientists have unearthed peculiar million-year-old rock tunnels in Africa, which have left researchers puzzled and suggest ...

Mysterious micro-burrows in desert marble and limestone were probably made by microbes that lived millions of years ago. Exactly what kind of microbes bored into the rock remains unknown, as does ...

The world’s longest and deepest undersea road tunnel is being built in Norway, intended to cut travel time between major cities and become part of a ferry-free highway along its western coast.

Probably Europe's largest deposit of rare earth metals, Kiruna's Per Geijer, is moving forward. The project is so massive ...

A nearly 20-mile underground relic of Nazi tunnels, shafts, underground railway stations and combat facilities in Poland can now be toured after being transformed into an army museum. The subterranean ...