The privately owned cemetery that holds room for Washington's finest when they step down from life.

A super-sized promotional trick that is now a D.C. landmark.

Government testing at the asylum briefly explored using marijuana as a "truth serum" on Nazi prisoners of war.

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

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

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

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

The United States Capitol's former columns still stand.

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

Every summer West Seattle experiences a housing bloom.

The school tested mustard gas for the U.S. Army during World War I.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

These medieval carvings bear scars left by Parliamentarian troops during the English Civil War.

The ruins of a defunct limestone quarry still haunt this Scottish promontory.

A community's effort restores the historical Maryhill Burgh Hall.

A humble ancient well where Scottish knight, Sir William Wallace, took his final drink.

A serene public space nestled within the remains of Glasgow’s Victorian maternity hospital

The small Scottish townhouse where the "Father of the National Parks" was born.

This centuries-old hotel hides a network of secret cellars and passages once used by smugglers.

A sea cave with a waterfall and Viking past

A secret door leads to this cozy dive that sells only “milk.”

Memorial to the Titanic engineers that died working to hold back the sea.

This Scottish castle has witnessed clan rivalries, Jacobite uprisings, whisky smuggling, and more.