Red light district
From The Art and Popular Culture Encyclopedia
A red-light district is a neighborhood where prostitution and other businesses in the sex industry flourish. The term "red-light district" was first recorded in the United States around 1890, and derives from the practice of placing a red light in the window to indicate to customers the nature of the business. The color red has been associated with prostitution for millennia: in the Biblical story of Rahab, a prostitute in Jericho aided the spies of Joshua and identified her house with a scarlet rope.
Some say the origin of the red light comes from the red lanterns carried by railway workers, which were left outside brothels when the workers entered, so that they could be quickly located for any needed train movement.
In more recent years the red-light district term has its name from the red lights that hang from the district's brothels.