You’ve got to hand it to William Mumler. In the 1860s, when the art of photography was still relatively new and shrouded in mystery, Mumler built a reputation for capturing ghosts with his camera lens.

Perhaps one of the most famous examples of Spirit Photography is his portrait of Mary Todd Lincoln, the former First Lady of the United States, which featured the ghost of her deceased husband, Abraham Lincoln. Was the dead president really floating in the background? Of course not - but even when Mumler was charged with fraud and larceny, the ensuing trial couldn’t prove “beyond all doubt” that he was fabricating the photographs.

So, Mumler was exonerated. Still, it did cast a shadow over his credibility, and his career as a spirit photographer was essentially over.