One of the steepest streets in the United States makes an intriguing challenge for cyclists.

The world's longest known cave system.

This former tuberculosis research hospital endeavored to cure the dreaded disease with fresh air and positive attitudes.

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

Live long and prosper in Tennessee.

One of the few surviving "Wigwam"-themed motels.

A local scoured more than 1,000 acres for stone to create his masterpiece.

This abandoned dream castle and its cemetery look out over the city that once inspired their creation.

A ship that lived many lives under many names is now known merely as the "Ghost Ship."

An office built to look like a giant basket.

Despite its lavish ornamentation, and wholesome lifestyle of its devotees, this mountain commune has faced its share of issues.

A castle built by an eccentric medieval enthusiast in rural Ohio.

An abandoned relic of the city's failed experiment with below ground transit.

Beyond the usual stories that attend old prisons, this one has deep bloody undercurrents.

The largest burial mound in the United States holds the remains of prehistoric West Virginians.

Visit this playground of waterfalls, caves and sinkholes.

A theme park featuring a replica of Noah's Ark built to the measurements specified in the Bible.

The remains of one of America's first radiation testing grounds still rest ominously in a Georgia forest.

After just one epic test blast, this literal loose cannon proved too explosive for combat.

This grave marks the final resting place of a legendary frontiersman... unless it doesn't.

This modern castle sat empty for decades before a fire inspired its builders to complete its luxury halls.

They call this long foot bridge a swinging bridge, but really it's the bouncing you have to watch out for.

Unique tower has outlasted a takeover of the company.

Outstanding collection of 19th century medical instruments includes a life-size figure cast from as many as 200 cadavers.