Overview
Labour Day is a day of first May every year that is celebrated in solidarity with labour. Paying tribute to them for their hard work. And a commitment for their health, safety, and well being.

History

This was in remembrance of the Haymarket Riots in Chicago in 1886, when a labour protest rally turned violent after someone threw a bomb at the police. According to the history.com, ”…at least eight people died as a result of the violence that day. Despite a lack of evidence against them, eight radical labour activists were convicted.”

Now it is linked to that moment. But mostly countries celebrated in solidarity with labours.

In the late 1800s, at the height of the Industrial Revolution in the United States, the average American worked 12-hour days and seven-day weeks in order to eke out a basic living. Despite restrictions in some states, children as young as 5 or 6 toiled in mills, factories and mines across the country, earning a fraction of their adult counterparts’ wages.

People of all ages, particularly the very poor and recent immigrants, often faced extremely unsafe working conditions, with insufficient access to fresh air, sanitary facilities and breaks.

As manufacturing increasingly supplanted agriculture as the wellspring of American employment, labor unions, which had first appeared in the late 18th century, grew more prominent and vocal. They began organizing strikes and rallies to protest poor conditions and compel employers to renegotiate hours and pay. (History.com)

How different countries celebrate labour day?

Overall its a solidarity day with laborers. But labour day is celebrated in different countries with different intentions.

Like in many American it is symbolized as the end of summer and benign celebrated with parties, parades and athletic events (History.com).

In Australia:

The first march for an eight-hour day by the labour movement occurred in Melbourne on 21 April 1856. On this day stonemasons and building workers on building sites around Melbourne stopped work and marched from the University of Melbourne to Parliament House to achieve an eight-hour day. Their direct action protest was a success, and they are noted as being among the first organized workers in the world to achieve an 8-hour day, with no loss of pay. (Wikipedia)

In Bangladesh

Bangladesh Garment Sramik Sanghati, an organization working for the welfare of garment workers, has requested that 24 April be declared Labour Safety Day in Bangladesh, in memory of the victims of the Rana Plaza building collapse. (Wikipedia).

To read more link to Wikipedia.