Once decrepit and slated for demolition, now one of the longest pedestrian bridges in the world.

This funicular railway rumbles along for a mile up the nearly vertical face of Chattanooga’s Lookout Mountain.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

A building so large that it has its own weather.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

The world's longest known cave system.

These fossilized remains of an ancient saber-toothed cat inspired the mascot of Nashville's NHL team.

A historic hotel library in Indiana hides more than a few secrets on its shelves.

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

This forest school's long history lets today's visitors experience resource management learnings in a beautiful environment.

Look closely and you’ll notice that the color changes a third of the way up the tower.

Washington's iconic carousel has a nice piece of Civil Rights history.

The statue mysteriously lost its head and left hand.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.

Northern Ireland's Brobdingnagian stepping stones.

These engineering masterpieces are a dominant feature of the Belfast skyline.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

Mysteriously stacked storefront paths give this medieval British town an iconic style like none other.

This picturesque archeological site looks like it was pulled straight from a fantasy novel.

Practice your Dirty Dancing lifts in the manmade lake where Johnny Castle himself did.

A 315-foot spire jutting out from the Blue Ridge Mountains makes for breathtaking views.

This rare basilica nestled right in downtown Asheville is an architectural marvel, inside and out.

Supplies are schlepped up by llamas at this century-old inn, accessible only by hiking trails in the Great Smokies.