The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

One of the greatest heroes of the Titanic tragedy came from humble beginnings to this beautiful home.

The home of one of America's most wealthy industrialists is now a historic site that remembers a more decadent time in the country's history.

Giant granite rocks standing end-to-end like a train of circus elephants.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

Overlooked amid the tourist bustle of Florence, this museum is dedicated to the craft of stone inlay.

The oldest operating pharmacy in the world features 800-year-old recipes.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

The middle finger of modernity.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

Secret refuge and museum of the Duke of Florence.

The iconic remains of the original Academic Hall that burned down in 1892.

The obelisk meant to mark the founding father's grave at Monticello is actually on the University of Missouri campus.

One of few surviving standpipe water towers in the U.S.

One of the world's earliest skyscrapers.

One man's unrequited love stands in a glass box forever.

The first rural cemetery west of the Mississippi is home to the elaborate tombs of St. Louis' local beer barons.

Speak to a companion on the other side of the room loud and clear through this architectural anomaly.

This mosaic-covered bar is brimming with curated curios.

Less a museum than a bizarre fantasy world created by artists and engineers.

This fancifully decorated Victorian home in New York’s Hudson Valley is the only known fully domed octagonal residence in the United States.

This giant rock arrived at this quiet park thousands of years ago on the back of a massive glacier.

In a historic steel foundry east of the Mississippi River, thousands of wooden crates hold the architectural remnants of buildings long gone but not forgotten.

In the St. Francois Mountains in the Ozarks at 1,772 feet above sea level, Taum Sauk Mountain is the highest (and possibly oldest) peak in Missouri.