This 38-drawer structure claims the superlative title, but it isn't the world's only giant filing cabinet.

This folk art dinosaur was almost pushed to extinction due to lack of a building permit.

Turns out you can see the world without ever leaving Maine.

A very big rock just plopped down in the New England woods.

This railroad tunnel was once the longest in Massachusetts.

The oldest badlands in North America, Makoshika State Park takes it name from the Lakota words for broken land.

This beautiful ancient site is dotted with perforated sandstone pillars considered sacred by some Native American groups.

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

Miraculous tree that seems to sprout out of solid rock.

The high point on the 16th president's eponymous roadway is marked by a massive version of his head.

Dance on a hand-hewn log floor padded with bouncy boxcar springs at a saloon built in 1883.

The highest peak in Utah is the hardest to reach, but only if explorers choose the hard way.

Sandstone rock formations that look like they belong on the cover of a progressive rock album.

These decaying bridges 1,000 feet high are a reminder of the skill it took to cross the Colorado Rockies by rail.

This old train trestle and collapsed tunnel once allowed the railroad to negotiate the steep slopes of the Colorado Rockies.

The remnants of a 1970 plane crash remain high in the Rocky Mountains.

The wreckage of a World War II bomber is hidden high in the Colorado wilderness.

Once a mortuary that held the remains of Buffalo Bill, this Denver hotspot is now a death-fixated restaurant.

The remains of the dam that unleashed a 15-foot wall of water on Denver.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

The largest self-built castle in the U.S., six decades in the making.

A partial tunnel blasted into a steep ridge is all that remains of a failed railway across Arizona.

The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

A well-preserved Ancestral Puebloan ruin tucked beneath a desert cliff.