In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

A massive underwater sinkhole made famous by Jacques Cousteau.

The ruins of a once-grand mansion in Northern Ireland are now thought to be haunted.

Mysterious 500-year-old tapestries depict a unicorn hunt.

Bowl in splendor, if you're lucky.

The rough and tumble president's childhood home displays the shirt he was once shot in and the speech that saved him.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A famous songsmith's custom piano, dubbed "High Society," is hidden just out of sight in one of New York's finest hotels.

The taxidermied remains of Charles Dickens' pet raven, which helped inspire one of Edgar Allan Poe's most famous poems.

A layered tribute to the work of mosaicist Isaiah Zagar.