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

America's first federal monument.

At 207 feet, one of the world's longest continuous escalators.

Parking garage where Bob Woodward met Watergate source "Deep Throat."

This museum devoted to the gothic author holds such interesting ephemera as his socks and walking stick.

A secretive collection featuring objects that were designed specifically for U.S. intelligence operations.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

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

Home of the physician who set the leg of John Wilkes Booth after the Lincoln assassination.

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

A benevolent, 16-foot-tall river dragon lives on a suburban lawn.

Remains of a historic fountain that was mysteriously lost in the demolition of a D.C. traffic circle.

Giant acorn-shaped 19th century gazebo from which suburban Washingtonians gazed upon the original "silver" spring.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

A star fort along the C&O Canal in western Maryland that protected America in three wars.

A monumental statue of RCA's mascot now sits atop a historical society roof after a life of moving around.

A pre-Industrial Age iron furnace and the site of a nearly-forgotten piece of Black history.

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

This scenic Maryland park was the site of one of the worst prison camps of the Civil War.

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

A blank headstone topped with a pile of pennies marks the final resting place of the infamous assassin.

A Civil War Museum with some notable medical antiques.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.