Where America's first doomsday cult awaited the end of the world.

Go inside to really appreciate this 500-year-old technological masterpiece.

The only museum with its curator—and her pets—buried inside.

Venice's "Island of the Mad."

Scattered throughout London are ancient remnants of the city's former bounding wall.

Hear the quietest sound from across the dome.

Museum dedicated to the UK's first charity for abandoned children, with keepsakes of the mothers who left them behind.

An unusual round church in London with a Templar past.

Giant, friendly pelicans in Central London, the most unlikely of places.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

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

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

An ornate tower shows off a local artist's architectural flair.

The Gaudí-inspired building that was the start of Terrassenc modernism.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

Turntable anonymously received orphans, alms, and groceries.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

Commonly acknowledged as the only public monument to the Devil himself.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

The birthplace of the builder of the Statue of Liberty is now a museum dedicated to his work.

A copy of the Statue of Liberty greets visitors to the birthplace of Auguste Bartholdi.

Along the Rhine, about a mile from the historic Munster, learn the heartrending story of two lovers torn asunder, cast into unknown layers of time and space.

One of the world's largest collections of pharmaceutical artifacts.