An 18th-century Spanish watchtower made entirely of seashell and concrete.

There is an unmarked red button hidden over Houston's Buffalo Bayou that is just begging to pushed...

This 15-foot former Johnny Appleseed has given up his apples for donuts and coffee.

Beer lover's can-covered house.

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

A small town built on an abandoned airfield has former runways as streets and a bar and grill in an old airplane hangar.

Massive still life just off the highway in Kansas.

An experimental, automotive replica of Stonehenge.

Open day and night, a church with three pews and Bibles.

Colorful boxes placed over the dead are left to rot and crumble.

A humid oasis combines recreation with exploration in a unique underwater cavern.

One of the only Florida forts to remain in the hands of the Union all through the Civil War still stands as a historic stronghold.

A high school astronomy enthusiast designed this model of our solar system to be traversed on foot.

An Alaska livestock farm devotes itself to harvesting wool from creatures that once ran with mammoths and sabertooth tigers.

A spiritual vortex among the red rocks in Sedona.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

This two-room shotgun shack in Tupelo is the birthplace of a King.

Coca Cola may be "the real thing" but its inventor, buried at this Georgia gravesite, called it a "valuable brain tonic."

This 1,500-acre development hopes to be the Central Park of the South.

The largest source of fossilized insects anywhere.

When ecosystems collide in the arid Southwest.

Roadside collection of 65,000 signs.

A surviving remnant of the thick ice mass that once mantled most of Western Canada's mountains.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.