Heron, whitewater rapids, and urban industrialism all add to the beauty of this concrete nature walk.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

Exact replica of the ancient monument, but much, much lighter.

A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

One family's mission to exemplify sustainability took on a whole new life as a surprisingly beautiful home.

Mineral springs believed to hold therapeutic properties draw in visitors from all over.

The inspiration for the Patagonia Clothing logo, Cerro Fitz Roy turns pink at sunrise.

A gateway to a mysterious network of underground tunnels.

Stenciled handprints and wall paintings dating back 10,000 years, some of the earliest forms of cave art.

Once swallowed by flood waters, this village has emerged as an eerie shadow of its former self.

A mine fire has been burning under the deserted town since 1962, but this church is still going strong.

A forgotten sea village stands silent after hurricanes deemed it obsolete.

This isolated structure beckons adventurers with sublime views of the Faroe Islands.