Día del Trabajo is an official holiday the day in many Latin American countries, so if you are visiting don't be surprised to find that many stores, banks, and other public services will be closed for the day. Instead, you will find parades, rallies, and festivals celebrating the workers and labor movements. This is also the day when many labor reforms (such as changes in salaries, minimum wage, and working hours) will be announced in recognition of workers' rights. Political rallies that have the potential of getting quite heated are also known to be held on this day, so it is probably best to avoid them and stick to the festivities when visiting Latin American countries on International Workers' Day.
In addition to all the celebrations held to show solidarity among the working class, the May 1st holiday, also called May Day, commemorates the traditional holiday welcoming the return of spring that began with the ancient festival for Flora, the Roman Goddess of flowers. May Day traditionally was honored by gathering flowers and dancing around the May Pole as a symbol of fertility and rebirth.
So for this first day of May, show your support for the working class in Latin America and around the world, but don't forget to stop and smell the roses!