This 19th century mansion façade adorned with immigrant patriotism is a symbol of Louisville’s history.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

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.

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

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

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

A Jenga-style cylindrical tower of books that appears to go on forever.

Two thousand artifacts from around the world collected by one woman who loved to travel.

The only National Monument ever to go missing for nearly 50 years then resurface in a dump.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.