One of many reminders of Tesla's scientific contributions overlooks the falls which inspired him.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

This whimsical fountain pays tribute to Toronto's four-legged friends.

A miniature representation of Canadian cities and landmarks in incredible—and sometimes hilarious—detail.

Known as "Toronto's Flatiron."

An exquisite Baroque church in Vienna's old town.

The solemn exterior conceals an opulent interior of this 17th century church.

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

Sweden's oldest animated sign is still lighting up the skyline today.

The Swedish flag over this small naval fort signals that the nation is at peace.

Stockholm's deepest subway station is also a stunning ecological wonder.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

Try not to get slimed in Tribeca.

Elevated freight railway turned wildly successful urban park.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

Go inside to really appreciate this 500-year-old technological masterpiece.

A former suicide bridge is now accumulating symbols of love instead of a body count.

Island wonderland for communist autocrats.

Disney's abandoned animal island is now an overgrown ruin that was almost the coolest attraction ever.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.