A walk through the historic city center, under the streets of Seattle.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

A 16th-century horror show built in a lovely Italian garden.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

This dramatic landscape hidden on the Isle of Skye looks as though you've stepped into the magical realm.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

The sign at the garden gate reads: "These Plants Can Kill."

A bizarre house filled with an astounding array of collections.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

Medicinal spa created with the discharge from a geothermal energy plant.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

France's most famous cemetery, with some of its most curious tombs.

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

The world's only museum devoted to the wonders of fluorescence.

These fantastically named natural pools look like something out of a Scottish myth.

A 140-year-old castle with underground caves hidden in San Francisco.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

A snapshot of the city's fascinating voodoo culture.