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

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

An oddities shop that dabbles in the deathly and beautiful.

The often-overlooked ruins of one of the first buildings designed by famous landscape architect Frederick Olmsted.

The ruins of this antebellum sugar plantation are the end result of a Seminole attack during the Florida Wars of 1836.

San Diego's most historic and haunted home.

Travelers exchange letters with woodland creatures at this mini post office.

A mysterious monument meant to be a guide into "an Age of Reason" was destroyed after an apparent bombing.

The restaurant keeps a hidden séance room on the second floor and reserves a table for the spirit of the former owner each night.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

A Bibliophile's Dream.

The name of this famed hospital was once a byword for the horrors of medical and psychiatric care.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

A self-built castle made by a mysterious man.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

The rocks in this arid basin leave trails of movement behind them.

This shop for all your super spy needs hides an educational secret.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

These Pre-Columbian petroglyphs contain representations of birds, deer, hunters, and even some early Native flute players.

The "Jade Museum" is full of thousands of intricately carved works of art made from various precious stones.

For posterity, a singular achievement: 3,780 hours of dancing.

A spooky defunct railroad tunnel now part of a sprawling trail.