This abandoned dream castle and its cemetery look out over the city that once inspired their creation.

Hollowed out cedar log tubs set in an ancient towering forest.

A heavenly experience, right here on Terra Firma.

A beautiful 62-acre Catholic shrine and botanical garden.

The seamy, underground secrets of Portland's criminal past.

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

One man’s religious convictions led him to build this stone castle meant to withstand an apocalypse.

This tiny 19th-century tunnel was built so a man could move his cows from one field to another.

The world's largest collection of porcelain "veilleuses-theiere," or night light teapots, includes four that belonged to Napoleon.

Over a dozen Native American earth mounds dating back over 2,000 years dot this Tennessee archaeological park.

One man has spent decades faithfully constructing this unique brick and cinderblock castle.

These early tent-shaped grave coverings are unique to Appalachia.

This park contains one of the largest concentrations of cedar glades, a unique and rare ecosystem.

Hiding behind a grocery store is a spectacular cavern carved as part of an old limestone quarry.

This large cave is a summer home to thousands of bats and has a rich history dating back to prehistoric times.

Mile-long cave system near Great Smoky Mountains.

Walk the whole Mississippi River!

This head-spinningly bizarre Depression-era art cave is wall-to-wall quartz and Jesus.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

This theater opened in 1998, but both the building and the puppeteers who perform there have a distinguished history.

One of America's oldest private membership libraries was long one of New Haven's best kept secrets.

One of the most scenic falls in Massachusetts has a history of death and grim legend.

An abandoned gun-funded 19th century utopia.