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

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

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.

Despite the ever pressing encroachment of urban sprawl this grand New Orleans manse still stands.

A wunderkammer of mysterious objects and stories.

Plagued with warts? Leave a frog at this small shrine in the city of Tosa, and you may be cured.

A massive cave complex boasts some of the clearest water (and most charming bats) in the world.

An eerie, decaying ghost town destined to fade into the forest.

A historic observatory now an astronomy museum beautifully situated at the moat of the Middle Age city centre.

The last occupied troglodyte dwellings in England weren't abandoned until the 1960s.

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

Nestled in the heart of San Francisco’s bustling Financial District stands a unique homage to the Mayan and Beaux Arts.

This odd Chilean waterfall-cano hotel must be entered via a rope bridge.

Railways may have forged this quintet of lovely tunnels, but now they are open to hikers.

Mysteriously stacked storefront paths give this medieval British town an iconic style like none other.

This 16th-century monastery has been turned into a surrealist architecture compound.

A theme park attraction designed to turn your children into LARPers.

Over thousands of years, this slot canyon was carved out of the bed of an ancient lake.

The menacing creature had a tremendous influence on the local culture before being exposed as a hoax.

A fairytale art house in the middle of Wisconsin.

Every winter, the wind carves blocks of frozen water into beautiful abstract shapes inside this unusually curved tunnel.

Vikings and Evangelicals have both had a hand in this replica medieval church.

Wisconsin's most celebrated export gets the royal treatment on I-94.