This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

A chilling disappearance (and rescue) of a child uncovers a geological mystery.

These beautiful wineries were at the center of Lake Erie's "grape belt" back when the Midwest dominated American wine production.

This stunning gothic ruin was a casualty of the Indiana steel industry crash.

The site of a 19th century "dream city" that almost rivaled Chicago before being swallowed by the Indiana sand dunes.

This old steel industry company town has a tradition of parking cars on the sidewalk so people can walk in the narrow streets.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

A century-old network of freight tunnels underneath the city's historic business district.

This once rural mansion now sits in the heart of the city.

An experimental, automotive replica of Stonehenge.

Other-worldly rock formations and ancient fossils abound in this unique stretch of Nebraska badlands.

This erect, phallic geological spire wasn't always named so domestically.

This magical-looking island is notorious for the misfortunes suffered by its owners.

A graceful natural rock formation stands astride the point where the Gulf of California meets the Pacific Ocean.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

Unlike most arches, this geological oddity formed in a volcanic dike.

This bird-shaped rock formation defies gravity, time, and classification.

This magnificent arch is all that remains of a former smelt mill.

This clifftop arch is a natural stunner.

Hidden in the hills is a mysterious stone structure, known only to a few.

The hallowed remains of a 900-year old Ancestral Pueblo great house.

Apparently, the whole cosmos emanates from this plain concrete tower.

The most powerful laboratory radiation source in the world pulses with 1,000 times the electricity of a lightning bolt.

On the edge of the Valles Caldera National Preserve, these rock formations create an eerie landscape.