Labor Day the Knights of Labor, which organized the first parade in New York City. In 1887, Oregon was the first state of the United States to make it an official public holiday. By the time it became an official federal holiday in 1894, thirty states in the United States officially celebrated Labor Day. Canada's Labour Day is also celebrated on the first Monday of September. More than 80 countries celebrate International Workers' Day on May 1 – the ancient European holiday of May Day. (May Day was chosen by the Second Internationale of socialist and communist parties to commemorate the Haymarket
Determination of the day of the week Determination of the day of the week The determination of the day of the week for any date may be performed with a variety of algorithms. In addition, perpetual calendars require no calculation by the user, and are essentially lookup tables. A typical application is to calculate the day of the week on which someone was born or a specific event occurred. In numerical calculation, the days of the week are represented as weekday numbers. If Monday is the first day of the week, the days may be coded 1 to 7, for Monday through Sunday, as is practiced in