Home to items never before seen by the public.

A diminutive memorial marks the site of a successful assassination by a right-wing death squad in America's capital.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Despite a fraught and controversial history this African island holds a powerful monument to the tragedy of the slave trade.

This tiny, tranquil Senegalese island serves as a powerful symbol of the Atlantic slave trade.

Once the fallout shelter of a dictator, this sprawling bunker is now a combined history museum and contemporary art gallery.

The 19th-century pharmacy (now a used bookstore) was featured in James Joyce’s "Ulysses," and has changed very little to this day.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

An eerie, existential museum dedicated to the author of "The Metamorphosis."

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Macabre astrological automaton clock dating to the late 1400s.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

A powerful tribute to the victims who suffered under Ethiopia's most devastating regime.

Supposedly this Ethiopian chapel holds the Ark of the Covenant, guarded by virgins who cannot leave the building.

The village's cobblestone streets are lined with shops displaying exquisite copper craftsmanship.

This mysterious but iconic tapered tower appears in many Azeri fairytales and legends.

This massive monument was unveiled the day Kosovo declared independence from Serbia.

Huge abstract sculptures of the Puerto Rican Flag.

An actual 1957 Cadillac De Ville, encased in 15 cubic yards of concrete.

One of the largest pieces of scientific equipment ever carried on a NASA space shuttle sits in a Chicago alley.

Home to a protest movement, a bombing, and a dramatic change in labor history.

This bronze sculpture on a former squash court marks the secret origins of the Atomic Age.

The site of the first couple's first kiss is commemorated by the most adorable presidential monument ever.