You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

Four bald cypress trees in Lafayette Square, across from the White House, mark the southern edge of a 100,000 year old cypress swamp.

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

It was once the base for a series of domestic terror attacks.

A Spiritualist house of worship where believers communicate with the dead in the spirit world.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

This park contains a number of standing stones meant to heal and inspire.

A unique hanging cable-car navigates through Dresden, the oldest suspension railway in the world.

Slaughterhouse Five opens its dank doors to fans of Kurt Vonnegut.

The largest treasure hoard in Europe is contained in a castle that was bombed out during World War II.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

In addition to fine dairy products, the world's most beautiful milk shop also offers a feast for the eyes.

This captivating Bronze Age timber circle spent centuries concealed by the tides.

This sweet Southern elixir comes from what may be the oldest grape vine in North America.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

When Azorean green tea meets volcanic hot springs water, a luminous brew is born.

Buried for centuries, this hidden cellar is all that remains of London's medieval Whitefriars Monastery.

In the mid-19th century, an eight-sided house was the latest fad.

Aged nearly 1,700 years, the world's oldest bottle of wine is probably still drinkable.

A mining town, now abandoned, was built in a canyon so narrow that the railroad ran right through the hotel lobby.

An iconic and controversial ancient Iberian funerary urn with a hauntingly penetrating gaze.