America's first serial killer rests in anonymity.

A 140-year-old castle with underground caves hidden in San Francisco.

A meteorite-bounded town in Bavaria.

Travel through the hidden underbelly of the city in colorful tunnels filled with art and history exhibits.

The ruins of this prominent glass factory yield hidden treasures buried among the jungle floor.

Fascinating museum dedicated to the under-appreciated medical history of urology features some wince-inducing devices.

A priceless collection of the Nation's cryptologic history.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The remarkably well-preserved final resting place of a powerful ancient Thracian king.

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

The Roman Emperor's lost summer home and grotto full of enormous sculptures sit along the Italian seashore.

The museum calls itself the "National Museum of the Paranormal" and is full of eerie oddities.

This architectural beauty is the home to a personal collection of more than 600 examples of mechanical musical instruments.

An archival collection of over 2,200 case studies which includes human brain specimens and tumor specimens.

This collection started by a Cornell professor once held more than 600 human brain specimens, including the one that belonged to its founder.

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

A downtown park built on top of unclaimed graves.

An encyclopedic collection of mammal penises.

Impressive sink holes fill this untouched old-growth forest in the Bahamas.

This 15th-century island fortress later served as home to the executioners no one wanted to live near.

The massive, incredibly rare instrument is over 11 feet tall with a range so deep it goes lower than humans can hear.

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.