An Australian lake whose pink hue defies scientific explanation.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

On the Oregon coast there is a natural hole that seems to be draining the sea.

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

Abandoned silver mine strewn with wrecked and twisted structures.

The remains of an idyllic small town built for the film 'Big Fish' still stand around a rundown main street.

Despite its name, this route in southern Utah offers a heavenly day trip.

The haunted reputation of these abandoned Colorado train tunnels is probably not helped by the terrifying spiked fence.

A winding, cliffside stretch of road overlooking the Delaware River.

This national park on the shore of Lake Michigan features remarkable dunes that lie at the heart of a Chippewa legend.

Once a menacing challenge for trailblazers, this trail is now the most scenic drive in Utah.

The quarry was abandoned over 100 years ago, after a massive ammunition explosion ended in tragedy.

This iconic Peak District ridge was once one of the busiest roads in medieval Britain.

A tunnel with windows, so you don't miss out on the impressive views.

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

The scant remains of this flooded historic village can be explored in one of the most remote areas of the Great Smokies.

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

Amalfi's pre-industrial history is slowly being engulfed by the lush vegetation of the Ferriere Valley.

This futuristically sylvan church is a glass-enclosed marvel of modern architecture.

This medieval hilltop village was abandoned at the end of the 19th century, after existing for more than 500 years.

148 feet long and in the middle of a verdant forest.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

An abandoned hotel in the highlands of Bali is shrouded in stories of ghosts, curses, and corruption.