An enormous natural sandstone bridge in Kentucky.

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

Once a place of peaceful repose, this sanitarium now faces an uncertain future.

Now abandoned, the first public health hospital in the U.S. saw more than one million immigrants from around the world.

Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

This award-winning men's bathroom was just too beautiful to not allow women to see.

This historic train station has been converted to a locomotive themed hotel.

A huge musical instrument played by the ocean.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

On a winding Vienna side street, one museum has turned their windows into a monument to history’s peace-minded heroes.

Apartment complexes built into huge repurposed natural gas tanks.

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

An exquisite Baroque church in Vienna's old town.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

The Habsburgs' royal collections of art and wonders.

This museum promotes informed contraception by documenting its often secret past.

This cubist Vienna church building looks like some sort of alien stonehenge.

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

Op-art architecture designed for happiness.

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

One of the best collections of wax anatomical models in the world.

Located right outside of Vienna, visitors can take in expansive views of an ethereal forest.

Macabre museum devoted to historical Viennese murders.

This former insane asylum now holds a pathological anatomy museum.