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

When it opened during the final years of the embargo, all the drinks and cigars were free.

An Industrial Revolution-era public work that purified water using nothing but sand.

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

People escaping slavery may have hidden inside a corpse vault.

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

A derelict bit of transportation infrastructure hidden in the woods.

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

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

A painfully obvious spy house sits right across the street from the Russian Embassy.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

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

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

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

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

A historic neighborhood church is reborn as a psychedelic arts collective.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

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

The United States Capitol's former columns still stand.