A stone arch leads to a cavernous 1930s spring house tucked away in the Pennsylvania woods.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A remarkable lava formation encloses a line of Buddhist statues that can't be accurately counted, according to local mythology.

This strategic isle was once swapped between empires and almost entirely destroyed in a bomb explosion.

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

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

Macabre astrological automaton clock dating to the late 1400s.

A trash dump made beautiful by nature's power.

The rocks in this arid basin leave trails of movement behind them.

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

A steaming, boiling hellscape sources Hokkaido's thermal baths.

A Japanese train station built around a 700-year-old camphor tree.

A set of ancient drawings in the desert of Peru that are so massive, many of them can only be fully seen from the sky.

Be(w)ar(e) the moat around this historic Czech castle.

Petrified footprints of one of the very first vertebrates to walk on land.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

Traversing steep Alpine slopes, this engineering marvel is one of the longest and highest funiculars in the world.

A waterfall runs right through the middle of this Taiwanese shrine to the hundreds of workers killed while building a nearby highway.

An architect transformed this abandoned cement factory into his castle-like workshop.

This abandoned fishing settlement may well be the greenest village in the world.

A small window on Via Piella offers a lovely and rare peek at Bologna's lost canals.

This unassuming museum's slogan translates to “there is a limit of sadness, anxiety has no limits."