Bizarre Cavern.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

Ethiopia's "smoking mountain" is in one of the hottest regions on the planet and is home to two lava lakes.

Fire meets ice at the southernmost volcano on Earth.

Carved, egg-shaped stone with no explanation.

The New England cabin where an infamous British occultist conducted experiments in "magick".

A very big rock just plopped down in the New England woods.

A curious whirlpool formation supposedly capable of entangling or engulfing branches, tree trunks, or whole rafts full of hapless tourists.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

Rippling sand dunes frozen in the Arizona rock.

Virgil's many-mouthed gateway to the underworld.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

A massive underwater sinkhole made famous by Jacques Cousteau.

Over fifty whirling pools left by the glacial age.

Ruins of a German Castle on top of a towering stone pillar.

A spectacular cave and a beguiling lake.

Stalactites and stalagmites in a beautifully lit cave.

The world's brightest bioluminescent bay.

The world's highest and most dangerous infinity pool lies at the precipice of Victoria Falls.

An isolated dive site teeming with cnidarians.

A naturally beautiful, seemingly bottomless deep blue spring.

Mysterious craters may have been home to an ancient cult.