The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

What was once the largest mine in North America has left behind a hollow hill filled with bright blue waters.

The remains of a paranoid inventor's hidden workshop lie in beautiful ruins amidst a Canadian park.

These locks on North America’s oldest canal are named after a porcine rock formation.

This inexpensive lodging house was once a prison notorious for its inhumane practices.

One of the foremost Sherlock Holmes collections is hidden away at a Toronto library.

An enchanting tunnel of cypress trees leads to an old morse code station still used today.

This artificial archipelago was supposed to resemble a map of the world.

Crop circles inspired this whimsical garden in Germany.

This stunning mass of ice spans 121 square miles and is still growing.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

This tiny museum's sizable collection is jammed into a former underground public toilet.

This abandoned Brutalist treehouse is a hidden architectural relic.

These imposing walls and towers look more like the ruins of a fortress than a monastery.

A magical museum of fairy tale treasures near Cyprus' buffer zone.

An isolated, rusty phone booth commemorates Iceland's first international telegraph cable.

The colonial city's social history is reflected in its fanciful door knockers.

This unique sanctuary invites you to interact with the beautiful birds.

Thousands of American timepieces on display in the former clock-making capital of the country.

A rare permanent monument to the Scottish Travellers.

At the United Kingdom's only residential library you can sleep among the books.

An eight-sided home built during a brief octagon craze in the 1850s.

An important pilgrimage site for pagans and early Christians, named for a Celtic goddess-turned-saint.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.