This ruined castle is said to be the legendary keep of a Viking princess.

New York City's smallest piece of private property.

Commemorating the spot where the famous scientist fed his pigeons.

A commemorative plaque hides a door that leads down to the New York Public Library's underground book bunker.

A tiny replica of the iconic London landmark hides on the side of the steel structure.

Read a book next to a Midtown waterfall.

Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.

These fantastically named natural pools look like something out of a Scottish myth.

A Moroccan getaway in the mountain range that plays the Himalayas' stunt double.

A turn-of-the-century architectural marvel built on healing mineral springs and salt licks.

The romance of early commercial flight still fills this Art Deco destination.

This abandoned Civil War fortress is slowly being swallowed by the waters of Lake Borgne.

Once the site of a Native American harvest festival, this humble clearing later played an invaluable role in the birth of jazz.

The highest point in Washington state is a volcano covered in glaciers.

"The House That Love Built" is shying away from "The House That Ghosts Love."

A stone wall commemorates the legend of a ferocious dragon who literally got his butt kicked by a knight.

This facility, now a museum, once housed and trained U.S. Army Air Force pilots who flew during the Allied invasion of Normandy.

History is hiding at the Morean Center for Clay.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Nature and art meet in this curvy creation

Prone to disastrous fires, the city of San Francisco has the Guardian, a fireboat gifted by residents, to watch over them from the bay.

Nine of the very few concrete ships ever made in the U.S. are beautifully decaying off a Virginia pier.

Flip your own pancakes in this old sugar mill within a Florida state park.

Yugoslavia's biggest underground airport lies in ruins.