A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

To find the "unicorns of the deep" you've got to go downstairs.

This museum celebrating the almighty dollar lets visitors literally stand in the shadow of a million bucks.

This historic hotel invented the chocolate brownie.

This alley in downtown Chicago held the bodies of over 600 people after the fateful Iroquois Theatre fire.

These abandoned grain silos and tunnels are an urban exploration dream.

This stunning gothic ruin was a casualty of the Indiana steel industry crash.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Elvis's own personal tropical hideaway.

This Memphis recording studio launched the careers of Jerry Lee Lewis, Johnny Cash, and Elvis Presley.

A recreation of the doomed ocean liner in the middle of the Smoky Mountains.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

The uniquely-designed winter home and sculpture studio of Anna and Archer Huntington.

I-95's Tijuana-style celebration of kitsch at the Carolina border.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

It was once the base for a series of domestic terror attacks.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

Home to items never before seen by the public.

There are lots of hands and feet stamped in the cement in front of Grauman’s Chinese Theater, but Mel left behind something extra.

Scores of vintage street lamps shine along L.A.’s Miracle Mile.

Once close to extinction, there is no shortage of elephant seals on the beaches of Año Nuevo State Park.

Get up close to emus and ostriches, or buy their tasty meat.

This Big Sur waterfall drops 80 feet directly into the Pacific Ocean, and inspired the hillside house up top.