Enter My Secret Room

The Egyptian pyramids often had secret rooms, hidden passages and false burial chambers built into them, in an attempt to foil grave robbers. Secret rooms, however, have been built for a wide variety of reasons, some benign, and some with foul and loathsome intent.

In the prohibition era of the 1920s, secret rooms, attics and hidden basements would be turned into speakeasies. Huge stores of illegal alcohol were often kept in these hideaways, which were fitted with peep-holes so that visitors could be vetted before entering the premises. Many speakeasies, like Manhattan's "21" club also had complicated systems involving drop-shelves, where bottles of alcohol could fall into secret compartments as a security measure. "21" also had an invisible wine cellar, disguised behind a shelf of canned foods and hanging smoked hams, which slid back to reveal the liquor cache.
New York's 21 Club was a Prohibition-era speakeasy.
Mobsters and Murderers

If you were interested to buy a house with a whole suite of secret rooms, enclosed behind a bank vault door, set in a guard-gated community in Las Vegas, there was recently a house on the market owned by a former mobster. Featuring hidden gun compartments and sump pumps to keep the water out of the deep basement rooms, the décor is, however, decidingly 1970s. There is also a soundproof concrete and steel room, with no inside doorknob! A film was made about the owners of this property called Casino, starring Robert De Niro.

Dr. Henry Howard Holmes (alias) was America's first serial killer who purposely built a horror hotel, to suit his evil intentions. Known as the "Murder Castle", the imposing structure occupied a whole block and was three-stories tall. Like a maze, the hotel had more than 100 windowless rooms, false floors, secret passages, doors which opened into brick walls and various trap doors. Greased shafts opened into a glass-lined room, where poisonousness gas could be released. A basement room which sat not far under the outside foot path, also contained instruments of torture and a kiln.
The "Murder Castle"
New York Newspaper The World showing floor plan of Holmes "Murder Castle"
Abuse of Power

Terrible atrocities and horrors were experienced by vulnerable orphans in the underground rooms of the Haut de la Garenne Orphanage, on the British island of Jersey. After allegations of abuse, authorities found appalling evidence that the underground chambers were the sites of beatings, sexual abuse, enforced drug taking and extreme isolation of victims. Ankle shackles, stocks and canes were also found at the site. A victim of the crimes said that what happened in these secret rooms was "indescribable". A child's skull was also found under a cement floor.
Haut de la Garenne