A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

Abandoned railway line circling the city of Paris.

This Scottish bridge seems to compel dogs to leap to their death.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

A remote candy-striped mountain in the Peruvian Andes straight out of the pages of Dr. Seuss.

The last inhabitants of one of the U.K.'s most remote islands were evacuated in 1930.

Thirty creepy ghosts now inhabit this decaying 14th-century church.

The villagers of the coldest inhabited place on Earth adjust to unique challenges presented by day-to-day living.

The Victorian-era greenhouse is stuffed with tropical plants, and open 365 days a year.

The longest hedge maze in the world.

Woven tree art gives this towering Australian woodland a touch of mystical whimsy.

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

This nearly invisible wire transforms much of the city into one big, symbolic home on the holy day.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

The steepest classic funicular in the world glides along a dizzying incline.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

A once-thriving hotel in the Swiss Alps couldn't compete with climate change.

These ancient sunken lanes were naturally tunneled into the soft ground by countless footsteps.

This historic stone bridge has an entire neighborhood clinging to its sides.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

A town church once nearly submerged by the damming of a river is now hauntingly visible as the water recedes.