An extensive collection of fine art devoted to man's best friend.

One of only two commuter aerial tramways in the United States.

Try not to get slimed in Tribeca.

A fantastic place to see murals, and an important location in the history of Toronto's legal street art scene.

A collection of more than 12,000 shoes, displayed in a building shaped like a shoebox.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

This once-grand marvel of engineering is now 41 miles of scenic hiking trail.

The last of Philadelphia's wood-paved streets is now a landmark of terrible engineering.

Sweden's "good old days" painstakingly re-created in a model village.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

The castle still holds traces of the abandoned Roman fort it was built atop.

Recently restored menagerie of Victorian-era beasts.

A harem-inspired Moorish fantasy design in a Victorian-era Welsh castle.

An encyclopedic collection of mammal penises.

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

Budapest's Communist-era statues, banished to the suburbs.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

Museum dedicated to the terror regimes of Hungary.

Single runway interrupted by a busy road that cuts across its middle.

Portugal's National Pantheon has a history of curses, collapses and financial problems.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A series of playful yellow penguins share a serious message about the environment.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.