Boasting a 7.5-mile-long labyrinth of caverns and underground passages, this subterranean gorge plunges 479 feet into the ground, making it the largest underground canyon in Europe.

Maryland’s largest active underground coal mine changed hands last month after its previous operator, Canadian firm Corsa Coal, filed for bankruptcy and auctioned its assets to pay creditors. The new ...

To mitigate these risks by collecting overflow from smaller rivers and diverting it to the Edo River, the country spent 13 years building the Metropolitan Area Outer Underground Discharge Channel ...