Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

Baroque celebration of the end of the Great Plague of Vienna.

The solemn exterior conceals an opulent interior of this 17th century church.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

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.

Walk in the footsteps of the gods and straddle two tectonic plates.

An encyclopedic collection of mammal penises.

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

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

Once the largest windmill outside of Holland, with enormous 114 foot sails.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

There is no trying to fall in love with this Star Wars fountain, you just do or do not.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

Tiki luxury on Nob Hill.

This museum has a most unusual location: inside a giant, three-headed elephant.

A battle between nature and architecture in the Cambodian jungle.

A former French military respite turned jungle tourism hotspot.

Khmer Rouge's high security prison.