Strange red rock formations that have been attributed to a higher power for hundreds of years.

Volunteer-run library dedicated to exploring five decades of activism history.

A very classy 1920s-era bar right in Grand Central Station.

The Cold War-era "underground Pentagon" is a sprawling subterranean hideaway for the Defense Department.

The sprawling, eccentric estate of Ames and Ames, a brilliant botanist, and a genius inventor and artist.

Inspiring Herman Melville and Henry David Thoreau, Mount Greylock in western Massachusetts is the highest point in the state at 3,491 feet above sea level.

The grave of America's 11th president is not in some grand monument but instead it's hidden away on the grounds of the Tennessee Capital.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

This legendary urban waterfall creates a dazzling display of rainbows.

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

Inside houses a vast collection of military aircraft and missiles spanning the ages.

The world's first aircraft factory has been hiding inside an automobile plant for almost 80 years.

An unusual, super-sized grocery adventure awaits in an Ohio suburb.

The world's longest known cave system.

A series of waterfalls and pools that flow through the 'Ohe'o Gulch and into the ocean.

This black shoreline is made up of exploded lava particles.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

The inventor of a number of hybrid corn species is immortalized with a field of giant corn.

After a water tower painting was accused of being an ad, a simple fix was made that gave the city a motto.

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

The highest point in North Carolina and the United States east of the Mississippi River, Mount Mitchell is named after argumentative explorer Elisha Mitchell.

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

This magnificent Cincinnati graveyard is also a popular public park.

The largest ancient burial mound in Ohio.