Black Friday in the UK.
According to USEconomy website, Black Friday is the name given to the shopping day after Thanksgiving. It was originally called Black Friday because so many people went out to shop that it caused traffic accidents and sometimes even violence.
The name was first recorded in 1966 by Earl Apfelbaum, a dealer in rare stamps. In his ad, he said, "'Black Friday' is the name that the Philadelphia Police Department gave to the Friday following Thanksgiving Day.