You can find America's highest suspension footbridge at Grandfather Mountain in North Carolina.

This high point in the Great Smoky Mountains is said to be home to the chief of all bears.

The second-largest ceremonial mound in the United States is an artificial hill that is loosely shaped like a pentagon.

The land is home to swimming ponies and a legendary 18th-century treasure.

Moonbows over Kentucky.

The world's longest known cave system.

A statue honoring 44 continuous years of greeting passing ships.

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

Interactive modern and vintage submarine equipment, World War II relics, and submarine attire.

Ruins of a Carnegie family mansion on Cumberland Island.

"We Seceded Where Others Failed."

The highway's southernmost spot is a beloved local attraction.

The sign that drew attention to a young boy's cucumber stand is now the name of his fruit superstore.

This now-deactivated naval base defended the Florida coast for centuries.

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

A building so large that it has its own weather.

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 monument celebrating the idea of reaching inaccessible places.

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

The only Florida state park with publicly accessible caves.

A much more welcome kind of snowbird vacationer, manatees camp out in these springs every winter.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world’s largest coastal brick fortresses.

World War II-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers.

A scenic fort on the harbor protected Philadelphia from an attack that never came.