This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

An astounding collection of medical specimens, including bits of President Lincoln.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

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

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

The most decorated dog of World War I is preserved in the Smithsonian.

Perhaps the most scandalous statue of America's first president.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

The story behind the mysterious symbol painted in front of the historic university's famous Rotunda.

Outdoor exhibits explore the contributions of European, African, and indigenous peoples to American frontier culture.

A former mental hospital founded in the 1930s by a eugenicist who advocated for the forced sterilization of patients.

Go take a picture with the inventor of the daguerreotype photographic process.

This elaborate towering structure was once famed for its revolutionary height.

Crammed into a Baltimore row house is an oddities shop that sells everything from skulls to dead insects.

The trials and tribulations of marking Poe's grave.

World's first "penitentiary," meant to be humane, drove men insane.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

The final resting place of two (or three) presidents, one vampire, and 18,000 Confederate soldiers.

This unique museum cafeteria showcases the history and regional diversity of African American cuisine.

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

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

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

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."