A semi-scholarly approach to sex.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

A collection of oddities including Dr. Kevorkian's suicide device, the Thanatron.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

Most-visited and most-photographed slot canyon in the American Southwest.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

World's first "penitentiary," meant to be humane, drove men insane.

A crumbling hospital from the 1850s on Roosevelt Island.

Rippling sand dunes frozen in the Arizona rock.

World's largest collection of serial killer artwork and other macabre exhibits.

Every equinox this Maya pyramid puts on a spooky ancient light show.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

The world’s first museum dedicated to exploring human rights unleashed a wave of controversy.

Thanks to its curved shape, this incredibly durable dam "whispers" to visitors.

This massive mall has hundreds of shops, an amusement park, and a history of deadly amusement attractions.

Along with his smaller donkey pal, he guards the museum’s exhibits and memorabilia.

With a floor made of thick glass, this observation deck offers a full view of Sunwapta Valley's mountains and rivers.

The water swaps direction twice a day, whipping into a frenzy of whirlpools and rapids.