"We Seceded Where Others Failed."

The museum chronicling a treasure hunter's dream, fulfilled.

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

A building so large that it has its own weather.

Tour the world's largest deep-hole dimension granite quarry, where you can view the plant where gravestones are made and roll a ball down the outdoor granite bowling alley.

The world's largest fully steerable radio telescope.

One of the world's largest model railroads is a mind-boggling achievement.

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

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

World War II bunker still standing on the New Jersey beach.

A monument marks the location of the first successful steamboat demonstration.

A labor of love built by local hang-gliding enthusiasts, this ideal launch spot was outlawed by the authorities and has since been largely abandoned.

Bizarre Cavern.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

Tiny observatory made big contributions to the study of the Earth's motion.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

At 207 feet, one of the world's longest continuous escalators.

The site of the climactic scene from the classic horror film is now a historic landmark.

Giant acorn-shaped 19th century gazebo from which suburban Washingtonians gazed upon the original "silver" spring.

Remnants of a storybook amusement park hidden behind a strip mall.

An abandoned Jazz Age dream home and con man's hideout in Death Valley.

Ten 25-foot-tall, beehive-shaped kilns, abandoned in Death Valley.

The biggest solar telescope in the world helps reveal the secrets of our sun.

America's only nuclear missile silo open to the public.