A secret hotel room can be found inside this clocktower in the oldest city in Austria.

A pyramid in Central Europe of unknown origin.

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

The townhouse where the "Blood Countess" Elizabeth Báthory started her murderous career.

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

Ancient church constructed with a special wood that preserves prints from the past.

Once a year, the ruins of an ancient village come alive with hundreds of glowing farolitos.

A unique geological area spiked with wind-carved rocks that resemble teepees.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

It's easy to see why this eclectic architectural wonder has been dubbed the "Spaceship House."

The fictional star of "Breaking Bad" is memorialized with a real-life gravestone in his hometown.

The Boston square dedicated to the dark poet who was born nearby.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

A goblet-shaped rock that, according to lore, is the home of an elven hermit.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

An easy-to-miss garden in Boston's North End honors the mother of JFK and others who lost children in WWII.

Millions of numbers carved in glass represent the tattoos forced upon victims.

A centuries-old church stands as a testament to Boston's "father of architecture."

Historic Hull Street was actually the first street with a proper name in the Boston area.

This landmark cemetery in Boston was created more than 300 years ago.

This nearly 200-year-old restaurant's history includes an exiled French prince, JFK, and a very hungry Daniel Webster.

This historic patch of real estate offers a glimpse of colonial Boston.