A semi-scholarly approach to sex.

Elevated freight railway turned wildly successful urban park.

A crumbling hospital from the 1850s on Roosevelt Island.

World's first "penitentiary," meant to be humane, drove men insane.

This little-known collection holds everything from "Dracula" notes, to the manuscript of "Ulysses," to the forged works of Shakespeare.

A daily replay of the experiment that proved the rotation of the Earth.

The juke joint where legendary soul artists ate, drank, and made merry.

Elvis's own personal tropical hideaway.

Every day a troupe of pampered water fowl walk the red carpet to their favorite fountain.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

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

This historic train station has been converted to a locomotive themed hotel.

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.

At 135 years old and counting, this historic print shop is heaven for poster nerds and music buffs.

This replica of the Greek structure is in the heart of Nashville.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

In which a local geological marvel becomes a quaint roadside attraction.

A failed piece of Orientalism has become the proud symbol of a community.

These delicate buggers are some of the rarest fossils that have bubbled up from the Tar Pits.

The first AIDS memorial chapel in San Francisco and one of only a few in the U.S.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Its buzzing collection honors vibrator history.