America's largest man-made forest was planted in an effort to bring back the past.

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

Roaming bison and a spectacular view at the highest point in Nebraska.

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

Long before guestbooks and hotels, frontier travelers signed their names on this rock face.

An experimental, automotive replica of Stonehenge.

Just a man taking his prehistoric pet for a stroll.

One-of-a-kind preserved ruins of an abandoned 1880s church in Chicago's Pilsen neighborhood.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

Community bookshelf of 25-foot-tall book spines.

Undone by Prohibition, this abandoned brewery-turned-flour mill is now ready for its third act.

An abandoned concrete jungle surrounded by a lush park.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

A train station that was abandoned by the coal industry and was later converted into a cocktail bar.

On the outskirts of a reborn ghost town, a decaying post office remembers the bad old days.

An abandoned stretch of highway, deteriorating next to the operational one.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

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

A mysterious light floating in the trees of Arkansas may be a piezoelectric effect.

Rippling sand dunes frozen in the Arizona rock.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

A little-known subterranean street runs under some of the best-known buildings in Chicago's River North.