A historic 1890s architectural masterpiece with an iconic clock tower that, once open to the public, now faces an uncertain future.

Blighted Irish field and the ruins of a 19th-century cottage on the edge of urban Manhattan.

The world's oldest known salt mine.

This museum preserves the hand-dug tunnel that kept Sarajevo afloat during the Serbian siege.

Bridge that died in war and was resurected.

A whimsical bridge adorned with decorative dragons.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

Where the lovelorn find a home for their sentimental keepsakes.

A musical instrument played by the sea.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

This one-time health resort was used by aristocrats around the world.

The very first subway station in New York City is beautiful, decked out in chandeliers, and ... abandoned?

Go surfing on this urban wave, "hacked" by local surfers.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

A semi-scholarly approach to sex.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

Nature and beauty amidst pollution and industrial wreckage.

Try not to get slimed in Tribeca.

The saddest little diner in New York.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

The modern birthplace of Irish freedom.

Dublin's "Dead Zoo" serves as a window to Victorian museum design.

Once the tallest building in the world and the site of “the highest dinner ever held in New York” this building now holds the most expensive penthouse in the city.

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”