This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

A Hawaiian stairway to heaven—that you can't climb.

What remains of the summer palace of King Kamehameha III.

Hidden in a secluded Greek cove is a pristine beach marred only by the rusting smuggler's hulk stranded on its shores.

A spectacular cave and a beguiling lake.

This remarkable cave was discovered after a shepherd watched bees enter and exit through a small fissure.

Giant marble phalluses on the sacred island of antiquity.

The hallucinogenic center of the ancient world.

This legendary city has been a tourist attraction for centuries.

Hideout of thieves, monks, and goat-footed gods.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

The underground sanctuary of a mysterious ancient cult.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

The central mosque of this Mali town is entirely built from mud.

These homes carved into the mountains seem to defy the laws of nature.

A French chateau, failed utopian community, odd museum, and Stonehenge replica in rural Washington State.

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

This Oregon farm is dedicated to teaching people the professional art of tree climbing.

The second largest waterfall by volume in the U.S., Willamette Falls is outdone only by Niagara in the amount of water that is pushed northward.

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

Delightful disarray of found objects and clutter.

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

High Victorian fantasy created a fairytale castle out of a ruined fortress in Wales.