Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

The attic of a four-century-old canal house hides a clandestine church.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

The incorrupt tongue of the patron saint of lost things is venerated in this basilica.

The oldest botanical garden in the world that technically isn't the oldest.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Oldest Museum of the Netherlands is a true cabinet of curiosities.

A former plague hospital turned medical museum.

The works of poetry's biggest names grace the walls of the city of Leiden, all carefully painted by hand.

A curious collection dedicated to human and animal anatomy and pathology.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

The most confusing clock in New York.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

One of the largest underground systems runs under Canada's largest urban center.

Op-art architecture designed for happiness.

A beautiful but toxic fountain of mercury.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

The ancient latrines of the Greeks, in all their public glory.

Roman ruins top white travertine terraces formed by ancient hot springs.

This famous city eluded concrete detection until the early 2000's.

Turkish adventurer antiques in the heart of the Grand Bazaar.

A marvel of Byzantine engineering under the streets of Istanbul.

Breathtaking and huge 430 year old maps of Italy.