Visitors travel in trams viewing stalagmites, stalactites and a pretty underground waterfall.

Troll Church) is a marble grotto leading up to an underground waterfall.

Metro station is decorated with works by abstract artist António Dacosta and is well known for having an underground waterfall.

That creates a miniature, misting underground waterfall, except it isn't just water.

He'd gone over an underground waterfall once, he was sure, and had managed to suck a breath before being whisked onward.

For the most part they are blocked off now, although a local businessman excavated an underground waterfall, which he called Ruby Falls.

The Deepwild also encompasses a series of dragon lairs known as the Wyrmcaves and a huge underground waterfall called the Deepwall.

In cases where the gradient is steeper, underground waterfalls may be constructed with appropriate design features (usually linings) to absorb the energy with minimal erosion.

A gigantic underground waterfall!

Ruby Falls is a 145-foot high underground waterfall located within Lookout Mountain, near Chattanooga, Tennessee in the United States.