Sherlock: The Abominable Bride - Easter Eggs & Hidden Details

In the Victorian 221B, Sherlock keeps his tobacco in a Persian slipper on the mantelpiece, a detail taken directly from the original stories by Arthur Conan Doyle. In the modern series, this is updated to cigarettes being kept there.

Sherlock keeps his unanswered mail pinned to the mantelpiece with a jackknife. This is another specific detail about Holmes's domestic habits described in the original Conan Doyle novels.

In the flashback to Holmes and Watson's first meeting, they meet with Mike Stamford at the Criterion Bar. This is the same location where the meeting takes place in the original novel, "A Study in Scarlet."

In the present-day scene on the plane, Mycroft opens Sherlock's notebook and sees the word "Redbeard." This is the name of Sherlock's childhood dog, the death of which was a significant trauma for him, revealed in a later season. Its inclusion here hints at deeper psychological issues at play within Sherlock's mind.

Instead of the smiley face with bullet holes on the wall of the modern 221B, the Victorian flat features a painting of a woman at her vanity table which, from a distance, creates the optical illusion of a skull. This is a classic "vanitas" image, symbolizing mortality.

Inside a Victorian Sherlock's pocket watch is a photograph of Irene Adler, referred to as "The Woman." This is a nod to the story "A Scandal in Bohemia," where Holmes keeps her photograph as a memento of the one woman who outwitted him.