The ruins of a resort and casino sit on the banks of this blue hole spring that pumps 70,000 gallons of warm, clear water every minute.

In a 345-million-year-old cave that's 200 feet underground, dinner awaits.

You can find America's highest suspension footbridge at Grandfather Mountain in North Carolina.

The largest collection of model trains in the world is actually run using full-size locomotive technology.

A comprehensive collection of toy and model trains, largely from the mid-20th century.

Don't get it twisted: This is the oldest pretzel bakery in the United States.

During the holidays, a vintage subway train whisks New Yorkers back in time.

These towering spires and glowing walls are carefully crafted from hundreds of thousands of icicles.

The National Railway Museum in York is the largest railway museum in the world, attracting almost 1 million visitors per year.

A 19th century library favored by Edgar Allan Poe and H.P. Lovecraft, known by locals as "the Ath."

A glimpse into early 19th-century education.

The last vestige of a once substantial orchard and farm in the suburbs of Northern Virginia.

This local mascot has been a presence in the area since the 1960s.

The only labyrinth within the city of Alexandria.

This small museum houses rare airplanes from aviation's golden age.

In an effort to escape the horrors of slavery, one man mailed himself to freedom.

The Virginia farm where John Wilkes Booth met his grisly end is now largely forgotten.

The resting place of a Civil War celebrity's amputated limb.

The narrowest house in America is seven feet of pure spite.

One of the last active volcanoes on the Eastern seaboard.

This historic mansion was built as a symbol of love between a husband and wife.

Bubbling up from deep underground is the warm crystal clear water that fills the Warm Springs Pools, America's oldest spa.

An original apothecary from 1792.

Edgar Allan Poe's old dorm is now a shrine to the author's legacy.