Houses are tucked between, on, and underneath giant boulders.

Half of a waterfall goes into the river while the other half seems to disappear.

A tribute to Ponce de Leon's supposed quest for eternal youth.

A stunning, abandoned limestone quarry in southern Indiana provided the stone to erect the Empire State Building.

These Pre-Columbian petroglyphs contain representations of birds, deer, hunters, and even some early Native flute players.

This replica of the Greek structure is in the heart of Nashville.

A 90-year-old underground water reservoir offers a more industrial kind of tranquility.

A unique waterfall that some believe attracts the fairfolk.

The largest drain hole in the world.

A swing to dangle you off the very edge.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

This historic national park is covered in the stunning ruins of red rock pueblos.

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

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

The final resting place of a space program monolith.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

Abandoned bridge hidden deep in the San Gabriel Mountains.

Even Henry David Thoreau found this glacial pothole irresistible.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

An ethereal glowing blue ocean cave in Croatia.

Dig for your own trilobites in this goldmine of invertebrates.

Accessible only at low tide, the deserted island is dotted with World War II ruins.

This concert pavilion on the shore of the Great Salt Lake has been destroyed by fire, water, and disinterest but keeps coming back.