An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

Outsider art meets paleontology at this roadside reptile repository.

An eponymous directional signpost erected by the first president of the United States.

A whopping 14,000 copper coins cover this miniature fighter jet.

This monument traces the segregation line that inspired the first rural branch of the NAACP.

Eighty million natural history specimens call this gargantuan museum home.

As the glaciers retreated out of northern Wisconsin, this unique natural wonder was crafted.

This park harkens back to frontier life in Wisconsin.

These unusual rooms on wheels are holdovers from the 1960s.

This pun was simply waiting to come to life, and one defense contractor made it so.

The tragic death of 19-year-old Mabel Tainter in 1886 led to the construction of this unique Victorian-era theater in the northern woods of Wisconsin.

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

The world's tallest aluminum statue is also the world's tallest image of a winged Virgin Mary.

An astounding collection of medical specimens, including bits of President Lincoln.

FDR's Art Deco hospital tower was hopelessly inefficient.

There’s a hidden military meme engraved on the World War II Memorial.

20,000 pieces in a Frank Gehry-designed building.

An ornate Art Deco tile mosaic representing Nebraskan life, both modern and prehistoric.

A sprawling maze of used books piled from floor to ceiling.

An ode to the friendship between four Pacific Rim countries.

An inconspicuous footbridge beloved by San Diego locals.

L. Frank Baum wrote part of the "Wizard of Oz" series in this wooden Victorian beach resort.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

The pedestrian traffic signals in Brazil's teeming metropolis light up with clues to nearby landmarks.