The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

The site of Martin Luther King Jr.'s arrest as he attempted to have lunch.

A 6,888-carat piece of turquoise that bears a striking resemblance to the first President of the United States.

A glimpse of a waterfall is reached by a steel catwalk along a slot canyon located in an Ouray city park.

A dangerous narrow-gauge railroad once traced a route through this striking canyon.

A 2,000-year-old Adena burial mound located along a busy street in Columbus, Ohio.

The world's largest outdoor organ is played weekly by one of just two civic organists in the U.S.

A sculpture of the famous photograph stands on San Diego's "Greatest Generation Walk."

L. Frank Baum wrote part of the "Wizard of Oz" series in this wooden Victorian beach resort.

One of the few remaining carousels built by master amusement park carver Charles I.D. Looff.

This little blue house pokes out over the campus of UC San Diego, seven stories high.

An extraordinarily ornate museum in San Diego holds wondrous anthropological treasures.

Behind this beachfront shop lies a spectacular, colorful sea cave with an equally colorful past.

This simple gravestone remembers a pig who single-hoofedly raised $19,000,000 for the Navy.

This head-spinningly bizarre Depression-era art cave is wall-to-wall quartz and Jesus.

Elvis's own personal tropical hideaway.

This giant pocket watch is the third iteration of a local landmark that has been standing just off the Santa Fe Plaza for over 100 years.

Train cars and railroad artifacts abound at this restaurant devoted to railway history.

A creek tumbles over a series of step-like rocks to create this scenic water feature.

When it was built in 1929, this historic bridge was the only place to cross the Colorado River for 600 miles.

This lush 12-acre site was once named the finest Japanese garden in North America.

The penultimate and final resting places of British General Edward Braddock—minus a few bits and pieces.

A lion given to the prime minister somehow got stuffed and sent to Florida.

Bronze footprints mark the path where a civil rights leader tried to march in peaceful protest before being knocked unconscious.