The remnants of the fortress that saved Georgia from the Spanish still stand guard on their swampy island.

The third tallest lighthouse in America once guided author Stephen Crane to safety.

Ruins of a Carnegie family mansion on Cumberland Island.

The ruins of this antebellum sugar plantation are the end result of a Seminole attack during the Florida Wars of 1836.

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

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

It's a pretty creepy lock-up.

A tribute to Ponce de Leon's supposed quest for eternal youth.

This Florida sinkhole hides a rainforest-like micro-environment in its depths.

The scuba diving training facility was named for the steam that rises from the cave's chimney.

One of the world’s largest and deepest freshwater springs, where mastodons once roamed.

FDR hoped to find a cure for polio in this Georgia town's warm springs.

This 13-foot smiling peanut in Georgia helped Jimmy Carter win the 1976 presidential election.

This state park was once an important Native American cermonial center.

The largest ancient burial mound in Ohio.

A historic coal mine that doubles as a museum and tourist attraction.

The world's longest known cave system.

One of the few surviving "Wigwam"-themed motels.

A collection of huge Pre-Colombian structures in Alabama.

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

This replica of the Greek structure is in the heart of Nashville.

The site where Confederate president Jefferson Davis was defeated has been marked with a bust... that leaves that part out.

The record holder for the world’s largest peach.

A 56-foot tall statue of the god of fire looks out over Birmingham, Alabama.