Helen Keller once broke ground on this historic center for the study of technologies to benefit the hearing impaired.

While knives are the main feature in this store, visitors will also find dinosaur bones and meteorites.

A recreation of the doomed ocean liner in the middle of the Smoky Mountains.

Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

The site of a gold-digging conquistador's bloody landing in the Americas.

Where pardoned turkeys once spent their all-too-brief final days.

A secret rendezvous spot where John S. Mosby and his Rangers would meet to divvy up their loot after raids.

This pun was simply waiting to come to life, and one defense contractor made it so.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

A creative deviation in this post office's design was once a source of controversy.

This former Cold War missile control site played an important role in the creation of GPS.

An out-of-place Air Force radar dome is all that denotes this park as a former missile launch site.

The only surviving 19th-century water-powered mill found in the Washington, D.C. area.

This "castle" is actually a limestone and quartz formation hidden along a trail.

Four metal statues of massive animal penises stand outside the university's Animal Sciences building.

The world's largest occupied bat houses hold hundreds of thousands of flying mammals.

A real (but thankfully not live) missile stands tall as a monument to the United States military in the small town of Cordele.

Ruins of a once-prized railroad station in New York.

A forsaken wonder in the middle of the East Side neighborhood.

One of Frank Lloyd Wright's greatest—and favorite—architectural masterpieces was almost lost.

The site of William McKinley's tragic assassination is only marked by an underwhelming boulder.

A beautifully designed asylum was resurrected as a hotel and art center with a ghost story or two.

This unique crypt designed by Frank Lloyd Wright for his longtime friend was not completed in either man's lifetime.

An unprepossessing stone marks the last resting place of one of the most accomplished Native Americans in history.