The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

One of Scotland's most important modern structures, it just made the '100 Most Endangered Sites' list.

The most loyal of little dogs, or a Victorian era publicity stunt?

Two women with a flair for both adventure and artful clutter created this singular round home.

This stately monument has been wearing a traffic cone hat for decades much to the delight of the locals.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

An old department store turned Nazi prison turned artist commune.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

This insurance company building reminds customers that witches, bears, and gnomes are out there, best be insured.

An alien church provides much needed silence in the midst of a Finland shopping center.

Flamboyant architecture from the turn of 20th century.

A black cat protests the City Guild in Riga's Old Town.

Sweden's "good old days" painstakingly re-created in a model village.

It houses the remains of a 17th-century version of the Titanic.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Ancient paintings known as the "Sistine Chapel of Cave Art."

Pilgrimage site for star-crossed lovers.

These medieval skyscrapers dominate the skyline of this small Tuscan town.

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

Breathtaking and huge 430 year old maps of Italy.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

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

One of Hungary's most influential places of learning is also home to one of the world's most beautiful libraries.

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