The remains of Crystal Palace Great Exhibition of 1851.

Smallest house in Toronto sits on a lot meant to be just wide enough for cars to drive through.

A giant can of fruit cocktail is all that remains of what was once the world's largest cannery.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

The world's last remaining store of its kind.

A grove of "candelabra redwoods" deep in California's Lost Coast.

This memorial includes fragments from one of the greatest tragedies in United States history.

A once-thriving hotel in the Swiss Alps couldn't compete with climate change.

The easternmost town in Alaska can only be accessed from Canada.

Elevated freight railway turned wildly successful urban park.

An underground mansion with fruit-bearing trees and grapes growing beneath the surface of central California.

Home to the only outdoor municipal elevator in the United States.

These old World War II fortifications have been transformed into an unusual equine attraction.

A remote desert lookout offers unparalleled views of the California badlands for those who brave the trek.

A retro walk through the history of the tube.

A futuristic hovertrain is parked unceremoniously alongside a nondescript road.

The abandoned train depot now doubles as a well-placed rest stop for those who take the road less traveled.

The largest self-built castle in the U.S., six decades in the making.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

A small museum dedicated to the whimsical tool that turns sugar cookies into works of art.

The illuminating collection of L.A. street lights is run by the city and only opens one day per month.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

Stairs often replace streets on the steep slopes of this old mining town.