This lake in the Cascades lives up to its name, disappearing down a hole every spring.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

The oldest operating apothecary in the US has treated everyone from Thomas Edison to Mark Twain.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

Less a museum than a bizarre fantasy world created by artists and engineers.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

The intriguing personal collection of a professional demon-chaser.

A tiny red pebble marks what may be the quietest outdoor spot in the United States.

Canyon walls shrouded in ferns.

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

This charmingly homemade amusement park has been growing for 40 years.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

A colorful architectural gem in Seattle's uniquely modern Central Library.

A bizarre roadside attraction and the first instance of miniature golf in the world.

An abandoned relic of the city's failed experiment with below ground transit.

The longest navigable underground river in the United States is home to countless blind and albino animals.

This maze-like slot canyon is a unique gem within an already fascinating geological area.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

The restaurant keeps a hidden séance room on the second floor and reserves a table for the spirit of the former owner each night.

A masterpiece of LGBT art has been restored in what may now be the most valuable restroom in America.

European castle ruins in an American state park are actually the product of death and grief.

This woodland architectural installation acts as a camera obscura for the heavens.