These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

Odd outsider art installations surround a Gold Rush-era ghost town.

A winding path built in secret on the edge of the continent.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

One of the world's oldest and most massive living organisms is a grove of quaking aspens.

Order scoops of pandan, lychee, and black sesame at this family-run institution.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

Stroll through a wonderland of stupendous moss-covered trees.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

An underground mansion with fruit-bearing trees and grapes growing beneath the surface of central California.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Mysterious rocks that ring musically when struck.

A layered tribute to the work of mosaicist Isaiah Zagar.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

The ghostly remains of an accidental sea.

A trash dump made beautiful by nature's power.

A psychedelic labyrinth on the San Francisco bay.

A bizarre house filled with an astounding array of collections.