Poland's oldest surviving university building holds a wealth of historic science instruments including some used by Copernicus.

A open air theatre built on a cliff by an eccentric British woman.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

These picturesque ruins crumble beautifully into the ocean.

London's smallest police station is barely the size of a phone booth.

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

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The modern birthplace of Irish freedom.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Rome’s legendary peephole vista is also a former Crusader stronghold.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

A giant bug impaled on a 75-foot-tall needle.

Notorious artist squat renovated into legal studios.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

This massive tea kettle was once a promotional stunt for the Oriental Teashop.

Regency-era excess on the English Coast.

A house of bones — but nobody is quite sure to whom they belong.

A fantastic castle rumored to be the birthplace of King Arthur.

Once a favorite playground for the world's most illustrious guests, Hotel Nacional's secret weapons and bunkers reveal a more menacing side to its golden history.

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

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