Although '21' was raided more than once, federal agents were never able to pin anything on Jack and Charlie. At the first sign of a raid, they would activate an ingenious system of pulleys and levers, which would sweep bottles from the bar shelves and hurl the smashed remains down a chute into the New York sewer system!
It was during this period that '21's famous Secret Wine Cellar was built.
Its two-ton door was unlocked by placing a meat skewer into a tiny hole in a certain brick. Investigators were further confused by the fact that the cellar was located not in number 21, but number 19, the house next door.
Want a bit more information on the architectural secrets of '21'? Read "Architecture and Construction History: The '21' Club" by Mr. Adam Gauntlett BA MA MSc RICS.