Londres. 1891- Facts

 

One of the girls that are kidnapped is Alice, Queen Victoria's granddaughter. Princess Alice (25 February 1883 – 3 January 1981), was a member of the British royal family. She was the longest-lived princess of the blood royal, and one of the longest-lived British royals. Princess Alice was the last surviving grandchild of Queen Victoria, the sister-in-law of Queen Mary, and the first cousin of Queen Mary's husband, King George V, and was the sister of Charles Edward the last Duke of Saxe-Coburg and Gotha.

Cox is a resurrectionist. Resurrectionists (or "resurrection men") were body snatchers who thrived in the late 18th and early 19th centuries by stealing recently buried corpses to sell to medical schools for anatomical dissection. 

Moriarty plans to create a phalanstere. A phalanstère was a type of building designed for a self-contained utopian community, ideally consisting of 500–2,000 people working together for mutual benefit, and developed in the early 19th century by Charles Fourier. 

There are many reference to the wall newspapers. A wall newspaper or placard newspaper is a hand-lettered or printed newspaper designed to be displayed and read in public places both indoors and outdoors, utilizing vertical surfaces such as walls, boards, and fences.

There is also a reference to the smog which killed many people in 1880. In the 1880s, London experienced frequent, severe "pea-souper" smogs caused by intensive coal burning, industrial emissions, and temperature inversions. These thick, dark-yellow fogs, such as those in January 1880, reduced visibility to near zero, paralyzed city transport, and caused significant mortality and respiratory illnesses, with smogs often killing over a thousand people in a single episode.

The girls that were kidnapped were locked in the human zoo, an idea of Carl Hagenbeck. While Carl Hagenbeck is often celebrated as the "father of the modern zoo" for inventing barless, moated enclosures, his legacy is deeply intertwined with the dark history of "human zoos". Hagenbeck became the world's most successful promoter of these "ethnographic exhibitions," which displayed people from non-Western cultures alongside animals and plants to recreate their "natural" environments. Hagenbeck’s most famous London exhibition took place at The Crystal Palace.

Charles Fourier is also a name that appears in the book. François Marie Charles Fourier (7 April 1772 – 10 October 1837) was a French philosopher, an influential early socialist thinker, and one of the founders of utopian socialism.

One of the men who Sherlock talks to says that the woman that the student who died befriended was an expert on numerology. Numerology is the ancient, esoteric study of the mystical relationship between numbers, letters, and life events, often used to understand personality, destiny, and timing. By calculating digits derived from a person’s birth date or name, practitioners believe they can unveil personal strengths, weaknesses, and future opportunities. 

She belonged to the Baraduc Society, based on the principles of Hyppolite Baraduc. Hippolyte Ferdinand Baraduc (November 15, 1850 – May 1, 1909) was a French physician and parapsychologist, highly known for his depiction of thoughts and feelings using iconography. Baraduc believed it was possible to photograph human mental states or emotions, such as grief and mourning, as well as the human soul. 

Rambalda surprises Cox when she drives a motorwagen. The Benz Patent-Motorwagen built in 1885 by the German engineer Karl Benz, is widely regarded as the first practical automobile and was the first car put into production. It was patented in January 1886 and unveiled in public later that year. 

Moriarty owns the painting "Le jeane fille a l'agneau' by Jean-Baptiste Greuze. Jean-Baptiste Greuze (21 August 1725 – 4 March 1805) was a French painter of portraits, genre scenes, and history painting.

Sherlock Holmes died in the Meiringen Falls. The Reichenbach Falls in Meiringen, Switzerland, is a spectacular 250-meter-high cascading waterfall famous as the site of Sherlock Holmes' final showdown with Professor Moriarty. Visitors can take a historic funicular to the top for views and hike to the marked spot of the fictional battle.