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

Behind an abandoned storefront is an example of pioneering 1930s gas station architecture.

This restaurant has been a haven for D.C.'s LGBTQ community since the 1950s.

Named after a militant urban guerilla, this famous former squat is a graffiti-covered stronghold of leftist culture.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

A historic ruin just 20 feet away from a busy highway onramp.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

An overlooked memorial honoring the local Washington residents who died in World War I.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

The national park was once a plantation estate.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

Rainbow-hued local gem in Venice.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

This beautiful, historic church looks like something out of a simpler past.

This stunning concert hall has become a symbol of Iceland's national recovery.

This natural Icelandic fissure allows divers to swim right between two volatile tectonic plates.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

An encyclopedic collection of mammal penises.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.