Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

Art deco landmark on the outskirts of Washington, D.C.

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

The oddly shaped, steam-spewing building is now an art studio and gallery.

Exact replica of the ancient monument, but much, much lighter.

A boardwalk winds above this beautiful bog full of wildlife and a rare type of turtle.

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

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

Quite possibly the last cross all humans will ever see.

Willy Wonka would love this weird half-a-home.

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

The Victorian-era greenhouse is stuffed with tropical plants, and open 365 days a year.

The Incredible Hulk, Yoda, Mulder and Scully, and many many others watch over the mean streets of Toronto.

This unusual structure may be on its way to becoming a cultural landmark in Toronto.

A memorial to the tens of thousands of Irish who fled to North America during the Great Famine.

One of the largest underground systems runs under Canada's largest urban center.

This colorful creation wasn't always a welcome part of Toronto's Moccasin Trail Park.

A book collector's dream, this Toronto bookstore has the world's first "Biblio-Mat," a random book vending machine.

This Toronto garden collects stares and tchotchkes in equal measure.

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

A haunting tribute to pioneering photographer Clover Adams.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

Giant acorn-shaped 19th century gazebo from which suburban Washingtonians gazed upon the original "silver" spring.