This shale formation along the Appalachian Trail once inspired the third president of the United States.

Built in the 1850s, this church was of the first five churches constructed in Harper's Ferry.

This historic boathouse was constructed using salvaged lumber from burned barns.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

The first memorial dedicated solely to the Black troops who fought for the Union.

This grand gothic brewery has been pumping out suds for over a hundred years.

A line of blue paint marks the route of the inaugural parade.

D.C. once had its own tiny rival to the New York Stock Exchange.

This nine-story building is the oldest standing skyscraper in D.C.

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

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

The Pentagon sits on a former island that was in Virginia at low tide and D.C. at high tide.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

These unusual rooms on wheels are holdovers from the 1960s.

An eerie natural formation that looks right back at you.

Crumbling pink walls and murder memorials preserve the pioneer history of Joshua Tree.

The decaying adobe remains of an old homestead are just off the beaten path in Joshua Tree National Park.

Get in line for Lisbon’s most famous sandwich.

Every weekend, the parking lot of this Buddhist temple turns into a Thai street-food paradise.

Literally a million fascinating cartographic artifacts are held in this sprawling university collection.

A Mayan village preserved for centuries in volcanic ash.

This color-changing crater lake in El Salvador is occasionally impenetrable to sunlight.