This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

A Civil War Museum with some notable medical antiques.

The bridge's highly-contested plaque (once again) honors Confederate President Jefferson Davis.

The United States Capitol's former columns still stand.

Surrounded by a verdant garden and a backdrop of ivy, a monument to beloved poet Khalil Gibran stands outside of the Lebanese embassy.

The house where John Wilkes Booth conspired with his co-conspirators.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

Home to items never before seen by the public.

The second oldest Jewish graveyard in the U.S. is tiny, with connections to George Washington and Henry Wadsworth Longfellow.

Designed to not only to represent the history of the local community but also, the future.

A 19th century library favored by Edgar Allan Poe and H.P. Lovecraft, known by locals as "the Ath."

Rumors of the occult haunt this upscale 1920s hotel.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

The medieval castle built as headquarters for the Pope's secretive Knights Templar.

Elaborate tile work in this railway station tells the story of Portugal.

Hidden beneath a beautiful overlook you’ll find the history of the city depicted in comic strip format next to a pay toilet.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

The corpse bride of Portugal.

The hippo that stands on this university campus was once a drunken flea market purchase.

This statue honors the author's groundbreaking family story.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."