Pompeii's less famous neighbor is still revealing her secrets.

The legendary building that needed ghostly approval before being built.

A tunnel once abandoned now thrives with graffiti art as an off-limits makeshift gallery.

This bridge is haunted by the ghost of a distraught mother.

In upstate New York, gorgeous waterfalls and a watermill are slowly being reclaimed by nature.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

Abandoned bridge hidden deep in the San Gabriel Mountains.

A self-made museum in Queens, New York continues to display the work of a sculptor known for paving his own way.

This tiny Bulgarian town offers a stunning location in the mountains and a storied history.

Eighteen miniature death-scene dioramas.

The charmingly disheveled clock tower of Tbilisi's puppet theater.

The first "Hall of Fame" in America was designed by legendary Gilded Age architect Stanford White for what was then the NYU uptown campus.

This abandoned Navy base was transformed into an off-grid alternative living community for thousands of people.

A local farm's collection of unusual structures from a now defunct storybook amusement park.

Twisted buildings adorn the banks of the Rhine river.

Michael Heizer's masterwork in the Nevada Basin.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

An exquisite tunnel of cascading flowers.

The Gaudí-inspired building that was the start of Terrassenc modernism.

An underground city of salt.

Reputedly haunted sandstone necropolis with exquisite stone carvings.