A curious memento mori hangs in the magnificent Cathedral of Segovia.

A psychological self-portrait in the form of a giant, segmented head.

An homage to Jackie Gleason's bus-driving character from 'The Honeymooners.'

There must be a pun in this haystack somewhere...

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

This giant iron playfully pays tribute to an early 20th-century architectural trend.

Debatably clever, or just plain honest hotel advertised as "The Worst Hotel in the World."

Amsterdam's narrowest house facade is a monument to 17th-century tax evasion.

A public urinal so pretty, it was declared a national monument.

This unattributed sculpture in Amsterdam is hiding in plain sight.

A beautifully eclectic mix of architectural styles.

Besides being home to cave paintings and pre-Columbian Cuban archaeological remains, you get to take a boat through this stalactite and stalagmite covered cave.

This 19th-century fountain's namesake animal isn't what you think it is.

Giant topiary dog once played a role in a terrorist bomb plot.

This 18th-century water provider for Aranjuez was refurbished in 2013 only to be neglected again.

This ancient Visigothic church might hide an ancient treasure.

Once the grandest synagogue in medieval Spain, it now stands as a memorial of the 15th-century Jewish exile.

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

These "mermaids" that surround a plaza in Segovia are rather sphinx-like.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

Dedicated to the humanitarian efforts of the state's former governor.

Hidden behind a wall, Spanish nuns distribute their signature sweets on a revolving tray.

A Spanish town built into the cliffs.