Go inside to really appreciate this 500-year-old technological masterpiece.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

The yawning maw of this pagan visage is said to bite off the hands of liars.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Three hundred years of preserved Spanish colonial history in San Antonio.

Housed in a century-old building, this museum's dedicated not just to soft drinks, but to the free enterprise system.

Visitors can walk over the largest concentration of Columbian mammoths to have died from one event.

Moonbows over Kentucky.

The only known Futuro house in North Carolina sits along a stretch of desolate highway on the Outer Banks.  .

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

Who needs fancy modern water slides when this giant North Carolina rock works just as well?

A historic covered bridge, only one of two remaining in North Carolina.

Once decrepit and slated for demolition, now one of the longest pedestrian bridges in the world.

A recreation of the doomed ocean liner in the middle of the Smoky Mountains.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

Enormous lake at the bottom of a unique cave system.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

The romance of early commercial flight still fills this Art Deco destination.

Scenic mount trashmore, Virginia Beach's most curious waterfront still has a couple of secrets.

A convincing little bit of ancient Egypt smack dab in Richmond, Virginia.

One street divides a single town that stands in two U.S. states.

This war hero's old shop remembers the fine line between medicine and quackery during the Revolutionary War.