A sinkhole opened up on a Midwest dairy farm in 1940 to reveal an underground river, a 21-mile cave system and rare creatures ...

Local porters ferry the expedition team’s equipment across an underground river to reach various chambers within the cave system. Author Neil Shea squeezes through a passage to enter a ...

More than 100 metres (328ft) beneath them is a lost world of ancient forests, plants and animals. All they can see is leafy ...

Many places around the world are famous for their beautiful underground rivers. The Puerto Princesa Subterranean River in the Philippines offers guided ...

To enjoy the caves safely and comfortably, wear shoes with nonskid soles and take a jacket. Complete your underground trips with a river trip or a walk on the River Styx Spring Trail. The least ...

which manages the nearly 300-acre Camuy River Cave Park. Highlights of the tour include the largest stalagmite in Puerto Rico, glimpses of the underground river (and maybe some bats), and a 450 ...

is an underground river and collection of caves. The bright turquoise water contrasts with the caramel- and mocha-colored rock formations within the caves, which include stalactites and stalagmites.

Škocjan Caves, the first Slovenian ... is considered the largest underground canyon in Europe. Inside it flows the Reka, the largest Slovenian sinking river. Considered the birthplace of modern ...