The world's longest known cave system.

This historic general store still operates much as it did in the late 1800s.

One of the world's largest automobile junkyards is a unique landscape of metal and moss.

An ideal wedding spot that is almost too ideal.

The Home and murder site of the witch of Rehmeyers Hollow.

The remains of a community that was forced to move for a dam that never materialized still rot in this Pennsylvania park.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

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

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

A toxic ghost town sitting atop a massive coal fire.

One man's swirling six-acre monument of stone.

This stone gatehouse was once the entrance to a historic mountain resort, and it had a cameo in a cheesy cult horror movie.

Conjoined twins Daisy and Violet Hilton were stars of the vaudeville circuit.

This North Carolina store preserves a historic moment in America's movement for racial equality.

These eerie outliers of the lightning bug family glow a mysterious blue color.

A forgotten sea village stands silent after hurricanes deemed it obsolete.

This research center for rare prosimians is studying how they sleep to help prolong human life.

This Cold War siren is one off the last of its kind still standing with its immensely powerful original horn.

Hundreds of hopeful gold miners came here to get rich, but only two years later the small town was deserted.

The final resting place of one of the most sensational guitar players of all time was created only after his father got the rights to his music.

The highest point in Washington state is a volcano covered in glaciers.

A short hike into the mountainside forest reveals a decaying 1890s town.

A logging-themed roadside restaurant surrounded by museum-quality machinery and artifacts from the industry's heyday.

The victims of a free-floating Japanese bombing during WWII are remembered by this stone monument.