This American Civil War-era fort still stands near the border between Washington, D.C. and Maryland.

The only Leonardo Da Vinci painting in the Western Hemisphere.

The revival of a classic Art Deco theater.

A statue based on a tragic Japanese nursery rhyme, commemorating San Diego's sisterhood with Yokohama.

An old pay phone rewired to play local bird calls and songs at the press of a button.

A priceless collection of the Nation's cryptologic history.

A set of rowhouses built for laborers at a glass company are the last of their kind in Annapolis.

Sip creative cocktails in the former vault of the Riggs Bank.

The FBI's urban training course may have the highest fake crime rate in the world.

Collecting 700 years of mechanical death-dealing, the NRA's sprawling gun museum is a revealing testament to the American obsession with armament.

This statue of the "father of television" stands prominently in the United States Capitol.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

Press 1 for knock-knock jokes.

Intricate, eye-catching, award-winning rubber sculptures liven up this Pennsylvania town.

A rare underwater observatory in the Caribbean that provides breathtaking views of vibrantly colored aquatic life.

An unexpected must-see for fans of Star Wars who find themselves on the beautiful island of Sint Maarten.

The life of one of America's pre-eminent painters is frozen in time in the home where he lived, worked, and died.

Fill your car with gas and your belly with mouthwatering Cuban cuisine at this takeaway inside a Citgo station.

A monument to one of the few Olympic flames ever to be lit outside of the host city.

Every autumn, this grove of living fossils erupts in a blaze of brilliant golden-yellow leaves and stinky fruit.

Famed activist Hellen Keller was involved in the operation and administration of this vacation home for blind women starting in the early 20th century.

This large garden vase urn has nothing to do with the seventh U.S. President—it was designed by one landscape designer to honor another landscape designer's contributions to the National Mall.

This large stone residence served as a field hospital during the Battle of Gettysburg between stints as a tavern.